Iteratively increase sample size for good/bad classification.

scripts/slave/recipe_modules/auto_bisect/example.expected/windows_x64_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 271 matching lines @@
     "cwd": "[SLAVE_BUILD]",
     "name": "Triggering test job for 314015",
     "trigger_specs": [
       {
         "builder_name": "chromium_rel_win7_x64",
         "properties": {
           "bisect_config": {
             "command": "src/tools/perf/run_benchmark -v --browser=release_x64 smoothness.tough_scrolling_cases",
             "max_time_minutes": "5",
             "metric": "mean_input_event_latency/mean_input_event_latency",
-            "repeat_count": "2",
+            "repeat_count": 3,
             "test_type": "perf"
           },
           "job_name": "a6298e4afedbf2cd461755ea6f45b0ad64222222-test",
           "parent_build_archive_url": "gs://chrome-perf/Win x64 Builder/full-build-win32_a6298e4afedbf2cd461755ea6f45b0ad64222222.zip",
           "parent_got_revision": "a6298e4afedbf2cd461755ea6f45b0ad64222222",
           "revision": "a6298e4afedbf2cd461755ea6f45b0ad64222222"
         }
       }
     ]
   },
@@ skipping 16 matching lines @@
     "cwd": "[SLAVE_BUILD]",
     "name": "Triggering test job for 314017",
     "trigger_specs": [
       {
         "builder_name": "chromium_rel_win7_x64",
         "properties": {
           "bisect_config": {
             "command": "src/tools/perf/run_benchmark -v --browser=release_x64 smoothness.tough_scrolling_cases",
             "max_time_minutes": "5",
             "metric": "mean_input_event_latency/mean_input_event_latency",
-            "repeat_count": "2",
+            "repeat_count": 3,
             "test_type": "perf"
           },
           "job_name": "00316c9ddfb9d7b4e1ed2fff9fe6d964d2111111-test",
           "parent_build_archive_url": "gs://chrome-perf/Win x64 Builder/full-build-win32_00316c9ddfb9d7b4e1ed2fff9fe6d964d2111111.zip",
           "parent_got_revision": "00316c9ddfb9d7b4e1ed2fff9fe6d964d2111111",
           "revision": "00316c9ddfb9d7b4e1ed2fff9fe6d964d2111111"
         }
       }
     ]
   },
@@ skipping 164 matching lines @@
     "cwd": "[SLAVE_BUILD]",
     "name": "Triggering test job for dcdcdc0ff1122212323134879ddceeb1240b0988",
     "trigger_specs": [
       {
         "builder_name": "chromium_rel_win7_x64",
         "properties": {
           "bisect_config": {
             "command": "src/tools/perf/run_benchmark -v --browser=release_x64 smoothness.tough_scrolling_cases",
             "max_time_minutes": "5",
             "metric": "mean_input_event_latency/mean_input_event_latency",
-            "repeat_count": "2",
+            "repeat_count": 3,
             "test_type": "perf"
           },
           "job_name": "dcdcdc0ff1122212323134879ddceeb1240b0988-test",
           "parent_build_archive_url": "gs://chrome-perf/Win x64 Builder/full-build-win32_dcdcdc0ff1122212323134879ddceeb1240b0988.zip",
           "parent_got_revision": "dcdcdc0ff1122212323134879ddceeb1240b0988",
           "revision": "dcdcdc0ff1122212323134879ddceeb1240b0988"
         }
       }
     ]
   },
@@ skipping 37 matching lines @@
       "----",
       "cat",
       "gs://chrome-perf/bisect-results/dcdcdc0ff1122212323134879ddceeb1240b0988-test.results"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "gsutil Get test results for build dcdcdc0ff1122212323134879ddceeb1240b0988",
     "stdout": "/path/to/tmp/"
   },
   {
     "cmd": [
+      "python",
+      "-u",
+      "RECIPE_MODULE[auto_bisect]/resources/significantly_different.py",
+      "[19, 20, 21]",
+      "[14, 15, 16]",
+      "0.05"
+    ],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "Checking sample difference",
+    "stdout": "/path/to/tmp/json",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@json.output (invalid)@null@@@",
+      "@@@STEP_LOG_END@json.output (invalid)@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_MODULE[auto_bisect]/resources/significantly_different.py",
+      "[14, 15, 16]",
+      "[14, 15, 16]",
+      "0.05"
+    ],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "Checking sample difference (2)",
+    "stdout": "/path/to/tmp/json",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@json.output (invalid)@null@@@",
+      "@@@STEP_LOG_END@json.output (invalid)@@@"
+    ]
+  },
+  {
+    "cmd": [
       "git",
       "show",
       "--name-only",
       "--pretty=format:",
       "dcdcdc0ff1122212323134879ddceeb1240b0988"
     ],
     "cwd": "[TMP_BASE]/fake_checkout_tmp_1",
     "name": "Checking DEPS for dcdcdc0ff1122212323134879ddceeb1240b0988",
     "stdout": "/path/to/tmp/"
   },
@@ skipping 192 matching lines @@
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]