Add bisect config validation.

scripts/slave/recipe_modules/auto_bisect/example.expected/basic_bisect_script.json

 [
   {
     "cmd": [
       "git",
       "update-ref",
       "refs/heads/master",
       "refs/remotes/origin/master"
     ],
     "cwd": "[TMP_BASE]/fake_checkout_tmp_1",
     "name": "git update-ref"
   },
   {
     "cmd": [
       "git",
       "checkout",
       "master"
     ],
     "cwd": "[TMP_BASE]/fake_checkout_tmp_1",
     "name": "git checkout"
   },
   {
     "cmd": [],
     "cwd": "[SLAVE_BUILD]",
     "name": "config",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@Bisect job configuration@{@@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"bad_revision\": \"314017\", @@@",
-      "@@@STEP_LOG_LINE@Bisect job configuration@  \"bug_id\": \"\", @@@",
+      "@@@STEP_LOG_LINE@Bisect job configuration@  \"bug_id\": \"-1\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"builder_host\": \"master4.golo.chromium.org\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"builder_port\": \"8341\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"bypass_stats_check\": \"True\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"dummy_builds\": \"True\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"good_revision\": \"314015\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"gs_bucket\": \"chrome-perf\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"max_time_minutes\": \"5\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"metric\": \"mean_input_event_latency/mean_input_event_latency\", @@@",
       "@@@STEP_LOG_LINE@Bisect job configuration@  \"recipe_tester_name\": \"linux_perf_tester\", @@@",
@@ skipping 930 matching lines @@
   {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/runtest.py",
       "--target",
       "Release",
       "--xvfb",
       "--factory-properties",
-      "{\"bisect_config\": {\"bad_revision\": \"314017\", \"bug_id\": \"\", \"builder_host\": \"master4.golo.chromium.org\", \"builder_port\": \"8341\", \"bypass_stats_check\": \"True\", \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", \"dummy_builds\": \"True\", \"good_revision\": \"314015\", \"gs_bucket\": \"chrome-perf\", \"max_time_minutes\": \"5\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"recipe_tester_name\": \"linux_perf_tester\", \"repeat_count\": \"2\", \"skip_gclient_ops\": \"True\", \"test_type\": \"perf\"}, \"buildername\": \"linux_perf_bisect\", \"mastername\": \"tryserver.chromium.perf\", \"recipe\": \"auto_bisect:example\", \"slavename\": \"dummyslave\"}",
+      "{\"bisect_config\": {\"bad_revision\": \"314017\", \"bug_id\": \"-1\", \"builder_host\": \"master4.golo.chromium.org\", \"builder_port\": \"8341\", \"bypass_stats_check\": \"True\", \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", \"dummy_builds\": \"True\", \"good_revision\": \"314015\", \"gs_bucket\": \"chrome-perf\", \"max_time_minutes\": \"5\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"recipe_tester_name\": \"linux_perf_tester\", \"repeat_count\": \"2\", \"skip_gclient_ops\": \"True\", \"test_type\": \"perf\"}, \"buildername\": \"linux_perf_bisect\", \"mastername\": \"tryserver.chromium.perf\", \"recipe\": \"auto_bisect:example\", \"slavename\": \"dummyslave\"}",
       "--build-properties",
-      "{\"bisect_config\": {\"bad_revision\": \"314017\", \"bug_id\": \"\", \"builder_host\": \"master4.golo.chromium.org\", \"builder_port\": \"8341\", \"bypass_stats_check\": \"True\", \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", \"dummy_builds\": \"True\", \"good_revision\": \"314015\", \"gs_bucket\": \"chrome-perf\", \"max_time_minutes\": \"5\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"recipe_tester_name\": \"linux_perf_tester\", \"repeat_count\": \"2\", \"skip_gclient_ops\": \"True\", \"test_type\": \"perf\"}, \"buildername\": \"linux_perf_bisect\", \"mastername\": \"tryserver.chromium.perf\", \"recipe\": \"auto_bisect:example\", \"slavename\": \"dummyslave\"}",
+      "{\"bisect_config\": {\"bad_revision\": \"314017\", \"bug_id\": \"-1\", \"builder_host\": \"master4.golo.chromium.org\", \"builder_port\": \"8341\", \"bypass_stats_check\": \"True\", \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", \"dummy_builds\": \"True\", \"good_revision\": \"314015\", \"gs_bucket\": \"chrome-perf\", \"max_time_minutes\": \"5\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"recipe_tester_name\": \"linux_perf_tester\", \"repeat_count\": \"2\", \"skip_gclient_ops\": \"True\", \"test_type\": \"perf\"}, \"buildername\": \"linux_perf_bisect\", \"mastername\": \"tryserver.chromium.perf\", \"recipe\": \"auto_bisect:example\", \"slavename\": \"dummyslave\"}",
       "--step-name=Running Bisection",
       "--builder-name=linux_perf_bisect",
       "--slave-name=dummyslave",
       "--run-python-script",
       "[TMP_BASE]/fake_checkout_tmp_1/tools/run-bisect-perf-regression.py",
       "-w",
       "[SLAVE_BUILD]",
       "--extra_src",
       "dummy_extra_src",
       "--path_to_config",
       "/dummy/path/",
       "--path_to_goma",
       "[BUILD]/goma",
       "--build-properties",
-      "{\"bisect_config\": {\"bad_revision\": \"314017\", \"bug_id\": \"\", \"builder_host\": \"master4.golo.chromium.org\", \"builder_port\": \"8341\", \"bypass_stats_check\": \"True\", \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", \"dummy_builds\": \"True\", \"good_revision\": \"314015\", \"gs_bucket\": \"chrome-perf\", \"max_time_minutes\": \"5\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"recipe_tester_name\": \"linux_perf_tester\", \"repeat_count\": \"2\", \"skip_gclient_ops\": \"True\", \"test_type\": \"perf\"}, \"buildername\": \"linux_perf_bisect\", \"mastername\": \"tryserver.chromium.perf\", \"recipe\": \"auto_bisect:example\", \"slavename\": \"dummyslave\"}"
+      "{\"bisect_config\": {\"bad_revision\": \"314017\", \"bug_id\": \"-1\", \"builder_host\": \"master4.golo.chromium.org\", \"builder_port\": \"8341\", \"bypass_stats_check\": \"True\", \"command\": \"src/tools/perf/run_benchmark -v --browser=release smoothness.tough_scrolling_cases\", \"dummy_builds\": \"True\", \"good_revision\": \"314015\", \"gs_bucket\": \"chrome-perf\", \"max_time_minutes\": \"5\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"recipe_tester_name\": \"linux_perf_tester\", \"repeat_count\": \"2\", \"skip_gclient_ops\": \"True\", \"test_type\": \"perf\"}, \"buildername\": \"linux_perf_bisect\", \"mastername\": \"tryserver.chromium.perf\", \"recipe\": \"auto_bisect:example\", \"slavename\": \"dummyslave\"}"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "Running Bisection"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]