The sSkippedTests is not incremented in the kGpuTestSkip check in
runTest, when it should be.

Bug: angleproject:3390
Change-Id: I4aca73ba1bbe3060fc3c0cd27679c2276a30a741
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1574620Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>