Stop to use contextmanager for goma.build_with_goma

scripts/slave/recipes/webrtc/libfuzzer.expected/full_tryserver_webrtc_linux_libfuzzer_rel.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--spec",
       "cache_dir = '[GIT_CACHE]'\nsolutions = [{'deps_file': 'DEPS', 'managed': True, 'name': 'src', 'url': 'https://chromium.googlesource.com/external/webrtc'}, {'deps_file': 'DEPS', 'managed': True, 'name': 'webrtc-limited', 'url': 'https://chrome-internal.googlesource.com/chrome/deps/webrtc-limited'}]",
       "--patch_root",
       "src",
@@ skipping 146 matching lines @@
     "name": "calculate targets",
     "stdout": "/path/to/tmp/",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@targets@target1@@@",
       "@@@STEP_LOG_LINE@targets@target2@@@",
       "@@@STEP_LOG_LINE@targets@target3@@@",
       "@@@STEP_LOG_END@targets@@@"
     ]
   },
   {
-    "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": [],
     "name": "preprocess_for_goma"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[CACHE]/cipd/goma/goma_ctl.py",
       "restart"
     ],
@@ skipping 22 matching lines @@
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "preprocess_for_goma.start cloudtail",
     "~followup_annotations": [
       "@@@STEP_NEST_LEVEL@1@@@"
     ]
   },
   {
     "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": [
       "RECIPE_PACKAGE_REPO[depot_tools]/ninja",
       "-w",
       "dupbuild=err",
       "-C",
       "[SLAVE_BUILD]/src/out/Release",
-      "-j",
-      "50",
       "target1",
       "target2",
-      "target3"
+      "target3",
+      "-j",
+      "50"
     ],
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "compile with ninja"
   },
   {
     "cmd": [],
     "name": "postprocess_for_goma"
   },
@@ skipping 49 matching lines @@
       "-u",
       "RECIPE_PACKAGE_REPO[build]/scripts/slave/upload_goma_logs.py",
       "--upload-compiler-proxy-info",
       "--json-status",
       "[CACHE]/cipd/goma/jsonstatus",
       "--ninja-log-outdir",
       "[SLAVE_BUILD]/src/out/Release",
       "--ninja-log-compiler",
       "goma",
       "--ninja-log-command",
-      "['RECIPE_PACKAGE_REPO[depot_tools]/ninja', '-w', 'dupbuild=err', '-C', '[SLAVE_BUILD]/src/out/Release', '-j', 50, 'target1', 'target2', 'target3']",
+      "['RECIPE_PACKAGE_REPO[depot_tools]/ninja', '-w', 'dupbuild=err', '-C', '[SLAVE_BUILD]/src/out/Release', 'target1', 'target2', 'target3', '-j', 50]",
       "--ninja-log-exit-status",
       "0",
       "--buildbot-buildername",
       "linux_libfuzzer_rel",
       "--buildbot-mastername",
       "tryserver.webrtc",
       "--buildbot-slavename",
       "TestSlavename"
     ],
     "env": {
@@ skipping 17 matching lines @@
     "~followup_annotations": [
       "@@@STEP_NEST_LEVEL@1@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]