Revert "Roll fuchsia/sdk/core/mac-amd64 from...

Revert "Roll fuchsia/sdk/core/mac-amd64 from Cx51FRV5TCoqQ9nfs4E2QMfYkJ1JWt7arQXhV01tr7cC to e8sS_5Rpuo7cSjSWPCdxwTEAg2VbS9NPH2tjhBhPwsUC (#9442)" (#9446)

Reverts flutter/engine#9442

Reason: this breaks "build fuchsia_debug" post-submit test (see https://ci.chromium.org/p/flutter/builders/prod/Mac%20Host%20Engine/928)

TBR: @cbracken 

DEPS

@@ -480,7 +480,7 @@ deps = {
      'packages': [
        {
         'package': 'fuchsia/sdk/core/mac-amd64',
-        'version': 'e8sS_5Rpuo7cSjSWPCdxwTEAg2VbS9NPH2tjhBhPwsUC'
+        'version': 'Cx51FRV5TCoqQ9nfs4E2QMfYkJ1JWt7arQXhV01tr7cC'
        }
      ],
      'condition': 'host_os == "mac"',