[infra] No relative path for infra_tests.isolate

This should allow dependent repos to use their own version of this
isolate file.

Change-Id: I5f20eafbd10319eef70ddb65b434269ca99d5c9f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/226416
Reviewed-by: Ben Wagner aka dogben <benjaminwagner@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
1 file changed