V8: Switch windows bots to mb

scripts/slave/recipes/v8.expected/full_client_v8_V8_Win64___clang.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
@@ skipping 110 matching lines @@
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]\\gclient.py",
       "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]\\v8",
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json",
+      "GYP_CHROMIUM_NO_ACTION": "1",
       "GYP_DEFINES": "clang=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",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\tools\\runit.py",
       "--show-path",
       "python",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\cleanup_temp.py"
     ],
     "name": "cleanup_temp"
   },
   {
+    "cmd": [
+      "python",
+      "-u",
+      "[SLAVE_BUILD]\\v8\\tools\\mb\\mb.py",
+      "gen",
+      "-m",
+      "client.v8",
+      "-b",
+      "V8 Win64 - clang",
+      "--config-file",
+      "[SLAVE_BUILD]\\v8\\infra\\mb\\mb_config.pyl",
+      "--goma-dir",
+      "[CACHE]\\cipd\\goma",
+      "--gyp-script=gypfiles\\gyp_v8",
+      "//out/Release_x64"
+    ],
+    "env": {
+      "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\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: 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@@@"
+    ]
+  },
+  {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\clang_revision.py",
       "--src-dir",
       "[SLAVE_BUILD]\\v8",
       "--output-json",
       "/path/to/tmp/json"
     ],
@@ skipping 46 matching lines @@
       "@@@STEP_LOG_LINE@json.output (invalid)@null@@@",
       "@@@STEP_LOG_END@json.output (invalid)@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]