refactor(nodejs): move build cop to flakybot (#540)

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Source-Link: googleapis/synthtool@57c23fa

packages/google-cloud-language/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/nodejs-language.git",
-        "sha": "b9fd685241ce21d19e42620425d2ec96dde27699"
+        "sha": "794f530137cc79c9d834befbeaeef70e9d414bd5"
       }
     },
     {
@@ -19,7 +19,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "363fe305e9ce34a6cd53951c6ee5f997094b54ee"
+        "sha": "57c23fa5705499a4181095ced81f0ee0933b64f6"
       }
     }
   ],