Update debug_web_tests to disable SpareRendererForSitePerProcess

As in
https://chromium.googlesource.com/chromium/src/+/1f09800130846fc877de40f5b673f9e409485853
the spare renderer confuses the script which expects there to be one and
only renderer.

The complexity of flags is unfortunately duplicated from debug_renderer
but could be combined later.

Change-Id: I42b21b8f434620228534f65df4077fbb426d640c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1627968
Auto-Submit: Robert Flack <flackr@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663337}
1 file changed