Add counting the number of CPU's in goma module

scripts/slave/recipes/bisection/desktop_bisect.expected/basic.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "\nimport sys, os\npath = sys.argv[1]\nmode = int(sys.argv[2])\nif not os.path.isdir(path):\n  if os.path.exists(path):\n    print \"%s exists but is not a dir\" % path\n    sys.exit(1)\n  os.makedirs(path, mode)\n",
       "[BUILDER_CACHE]/linux_perf_bisect",
       "511"
     ],
     "name": "makedirs checkout path",
@@ skipping 177 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": "[BUILDER_CACHE]/linux_perf_bisect/src",
     "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 107 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"
+    ],
+    "cwd": "[BUILDER_CACHE]/linux_perf_bisect",
+    "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",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"branch\": \"\", \"buildername\": \"linux_perf_bisect\", \"buildnumber\": 571, \"issue\": 12853011, \"mastername\": \"tryserver.chromium.perf\", \"patch_project\": \"chromium\", \"patchset\": 1, \"path_config\": \"kitchen\", \"project\": \"chrome\", \"recipe\": \"bisection/desktop_bisect\", \"repository\": \"\", \"requester\": \"commit-bot@chromium.org\", \"revision\": \"HEAD\", \"rietveld\": \"https://codereview.chromium.org\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
@@ skipping 14 matching lines @@
     ],
     "cwd": "[BUILDER_CACHE]/linux_perf_bisect",
     "name": "Running Bisection"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]