Stop to use contextmanager for goma.build_with_goma

scripts/slave/recipe_modules/goma/example.expected/win.json

Index: scripts/slave/recipe_modules/goma/example.expected/win.json
diff --git a/scripts/slave/recipe_modules/goma/example.expected/win.json b/scripts/slave/recipe_modules/goma/example.expected/win.json
index 0d336e8dcc2c54a59f308e0ead7b0643aabebbdd..0c449f428d36292a6fb5d13ea1c086f263dce5ec 100644
--- a/scripts/slave/recipe_modules/goma/example.expected/win.json
+++ b/scripts/slave/recipe_modules/goma/example.expected/win.json
@@ -89,52 +89,11 @@
   },
   {
     "cmd": [
-      "python",
-      "-u",
-      "\nimport multiprocessing\nimport sys\n\njob_limit = 200\nif sys.platform.startswith('linux'):\n  # Use 80 for linux not to load goma backend.\n  job_limit = 80\n\ntry:\n  jobs = min(job_limit, multiprocessing.cpu_count() * 10)\nexcept NotImplementedError:\n  jobs = 50\n\nprint jobs\n"
-    ],
-    "name": "calculate the number of recommended jobs",
-    "stdout": "/path/to/tmp/",
-    "~followup_annotations": [
-      "@@@STEP_LOG_LINE@python.inline@@@@",
-      "@@@STEP_LOG_LINE@python.inline@import multiprocessing@@@",
-      "@@@STEP_LOG_LINE@python.inline@import sys@@@",
-      "@@@STEP_LOG_LINE@python.inline@@@@",
-      "@@@STEP_LOG_LINE@python.inline@job_limit = 200@@@",
-      "@@@STEP_LOG_LINE@python.inline@if sys.platform.startswith('linux'):@@@",
-      "@@@STEP_LOG_LINE@python.inline@  # Use 80 for linux not to load goma backend.@@@",
-      "@@@STEP_LOG_LINE@python.inline@  job_limit = 80@@@",
-      "@@@STEP_LOG_LINE@python.inline@@@@",
-      "@@@STEP_LOG_LINE@python.inline@try:@@@",
-      "@@@STEP_LOG_LINE@python.inline@  jobs = min(job_limit, multiprocessing.cpu_count() * 10)@@@",
-      "@@@STEP_LOG_LINE@python.inline@except NotImplementedError:@@@",
-      "@@@STEP_LOG_LINE@python.inline@  jobs = 50@@@",
-      "@@@STEP_LOG_LINE@python.inline@@@@",
-      "@@@STEP_LOG_LINE@python.inline@print jobs@@@",
-      "@@@STEP_LOG_END@python.inline@@@"
-    ]
-  },
-  {
-    "cmd": [
-      "echo",
-      "50"
-    ],
-    "name": "echo goma jobs"
-  },
-  {
-    "cmd": [
-      "echo",
-      "50"
-    ],
-    "name": "echo goma jobs second"
-  },
-  {
-    "cmd": [
       "ninja",
-      "-C",
-      "out/Release",
       "-j",
-      "500"
+      "80",
+      "-C",
+      "out/Release"
     ],
     "name": "ninja"
   },
@@ -207,7 +166,7 @@
       "--ninja-log-compiler",
       "goma",
       "--ninja-log-command",
-      "['ninja', '-C', 'out/Release', '-j', '500']",
+      "['ninja', '-j', '80', '-C', 'out/Release']",
       "--ninja-log-exit-status",
       "0",
       "--goma-stats-file",