Add counting the number of CPU's in goma module

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

 [
   {
     "cmd": [
       "git",
       "update-ref",
       "refs/heads/master",
       "refs/remotes/origin/master"
     ],
     "cwd": "[TMP_BASE]/fake_checkout_tmp_1",
     "name": "git update-ref"
@@ skipping 882 matching lines @@
       "@@@STEP_LOG_LINE@json.output@    }@@@",
       "@@@STEP_LOG_LINE@json.output@  ]@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
+      "\nimport multiprocessing\nprint min(200, multiprocessing.cpu_count() * 10)\n"
+    ],
+    "name": "ensure_goma.get the number of cpus",
+    "stdout": "/path/to/tmp/",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@import multiprocessing@@@",
+      "@@@STEP_LOG_LINE@python.inline@print min(200, multiprocessing.cpu_count() * 10)@@@",
+      "@@@STEP_LOG_END@python.inline@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]/gclient.py",
       "runhooks"
     ],
     "cwd": "[TMP_BASE]/fake_checkout_tmp_1",
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json",
       "GYP_CHROMIUM_NO_ACTION": "1",
       "GYP_DEFINES": "branding=Chrome buildtype=Official component=static_library gomadir='[CACHE]/cipd/goma' target_arch=x64 use_goma=1",
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
     },
@@ skipping 61 matching lines @@
       "@@@STEP_LOG_LINE@json.output@    {@@@",
       "@@@STEP_LOG_LINE@json.output@      \"instance_id\": \"resolved-instance_id-of-release---------\", @@@",
       "@@@STEP_LOG_LINE@json.output@      \"package\": \"infra_internal/goma/client/linux-amd64\"@@@",
       "@@@STEP_LOG_LINE@json.output@    }@@@",
       "@@@STEP_LOG_LINE@json.output@  ]@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
+    "cmd": [
+      "python",
+      "-u",
+      "\nimport multiprocessing\nprint min(200, multiprocessing.cpu_count() * 10)\n"
+    ],
+    "name": "ensure_goma.get the number of cpus (2)",
+    "stdout": "/path/to/tmp/",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@import multiprocessing@@@",
+      "@@@STEP_LOG_LINE@python.inline@print min(200, multiprocessing.cpu_count() * 10)@@@",
+      "@@@STEP_LOG_END@python.inline@@@"
+    ]
+  },
+  {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]/scripts/slave/runtest.py",
       "--target",
       "Release",
       "--xvfb",
       "--factory-properties",
       "{\"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\", \"dummy_job_names\": \"True\", \"dummy_tests\": \"True\", \"good_revision\": \"314015\", \"gs_bucket\": \"chrome-perf\", \"max_time_minutes\": \"5\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"recipe_tester_name\": \"chromium_rel_mac\", \"repeat_count\": \"2\", \"skip_gclient_ops\": \"True\", \"test_type\": \"perf\"}, \"buildername\": \"linux_perf_bisect\", \"mastername\": \"tryserver.chromium.perf\", \"recipe\": \"auto_bisect:example\", \"slavename\": \"dummyslave\"}",
@@ skipping 16 matching lines @@
       "{\"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\", \"dummy_job_names\": \"True\", \"dummy_tests\": \"True\", \"good_revision\": \"314015\", \"gs_bucket\": \"chrome-perf\", \"max_time_minutes\": \"5\", \"metric\": \"mean_input_event_latency/mean_input_event_latency\", \"recipe_tester_name\": \"chromium_rel_mac\", \"repeat_count\": \"2\", \"skip_gclient_ops\": \"True\", \"test_type\": \"perf\"}, \"buildername\": \"linux_perf_bisect\", \"mastername\": \"tryserver.chromium.perf\", \"recipe\": \"auto_bisect:example\", \"slavename\": \"dummyslave\"}"
     ],
     "name": "Running Bisection"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]