V8: switch more linux bots to mb

scripts/slave/recipes/v8.expected/full_client_v8_V8_Linux64___gcov_coverage.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "client.v8",
       "--builder",
       "V8 Linux64 - gcov coverage",
@@ skipping 121 matching lines @@
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]/gclient.py",
       "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]/v8",
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json",
+      "GYP_CHROMIUM_NO_ACTION": "1",
       "GYP_DEFINES": "clang=0 coverage=1 gomadir='[CACHE]/cipd/goma' target_arch=x64 use_goma=1 v8_target_arch=x64",
       "GYP_GENERATORS": "ninja",
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
@@ skipping 10 matching lines @@
       "--directory",
       "[SLAVE_BUILD]/v8/out/Release",
       "--zerocounters"
     ],
     "name": "lcov zero counters"
   },
   {
     "cmd": [
       "python",
       "-u",
+      "[SLAVE_BUILD]/v8/tools/mb/mb.py",
+      "gen",
+      "-m",
+      "client.v8",
+      "-b",
+      "V8 Linux64 - gcov coverage",
+      "--config-file",
+      "[SLAVE_BUILD]/v8/infra/mb/mb_config.pyl",
+      "--goma-dir",
+      "[CACHE]/cipd/goma",
+      "--gyp-script=gypfiles/gyp_v8",
+      "//out/Release"
+    ],
+    "env": {
+      "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
+    },
+    "name": "generate_build_files",
+    "stdout": "/path/to/tmp/",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@stdout@some line@@@",
+      "@@@STEP_LOG_LINE@stdout@GYP_DEFINES='target_arch=x64 cool_flag=a=1'@@@",
+      "@@@STEP_LOG_LINE@stdout@moar@@@",
+      "@@@STEP_LOG_END@stdout@@@",
+      "@@@STEP_LOG_LINE@diff@+ cool_flag: a=1@@@",
+      "@@@STEP_LOG_LINE@diff@- clang: 0@@@",
+      "@@@STEP_LOG_LINE@diff@- coverage: 1@@@",
+      "@@@STEP_LOG_LINE@diff@- gomadir: '[CACHE]/cipd/goma'@@@",
+      "@@@STEP_LOG_LINE@diff@  target_arch: x64@@@",
+      "@@@STEP_LOG_LINE@diff@- use_goma: 1@@@",
+      "@@@STEP_LOG_END@diff@@@",
+      "@@@STEP_WARNINGS@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "RECIPE_MODULE[build::v8]/resources/patch_mb_config.py",
       "[SLAVE_BUILD]/v8/infra/mb/mb_config.pyl",
       "/path/to/tmp/"
     ],
     "name": "patch mb config (fyi)"
   },
   {
     "cmd": [
       "python",
       "-u",
@@ skipping 177 matching lines @@
     "~followup_annotations": [
       "@@@STEP_LINK@report@https://storage.googleapis.com/chromium-v8/linux64_gcov_rel/f2cbea7e89a45f46819777bb78a1f5bd0241f64c/index.html@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]