Fix build on Windows
Fix build on Windows

Without this check, Python ends up spawning lots of Java processes and filling console with errors instead of building.

See https://stackoverflow.com/a/18205006.

Change-Id: Ia9956f649a59ec372dce675adcce31f072d8ee7f
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/1883723
Reviewed-by: Tim van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>
Commit-Queue: Ingvar Stepanyan <62070607b8a20742f77a132d590706c0c02d8f9a@google.com>

ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend