Attempt to run Cors functional tests with watchman disabled. (#7076)

According to jestjs/jest#2219, jest will
not run tests if watchman is installed. It is not entirely clear if
this is the case in our OSX CI environment, but the symptoms seem close
to what's reported in the issue.

Possible fix for https://github.com/aspnet/AspNetCore-Internal/issues/1619

src/Middleware/CORS/test/FunctionalTests/CorsMiddlewareFunctionalTest.cs

@@ -37,15 +37,15 @@ public async Task RunClientTests()
  processStartInfo = new ProcessStartInfo
  {
  FileName = "cmd",
- Arguments = "/c npm test --no-color",
+ Arguments = "/c npm test --no-color --no-watchman",
  };
  }
  else
  {
  processStartInfo = new ProcessStartInfo
  {
  FileName = "npm",
- Arguments = "test",
+ Arguments = "test --no-watchman",
  };
  }