Also force ANGLE_SKIP_TEST_IF() to require a semicolon.

BUG=angleproject:2220
TEST=angle_end2end_tests

Change-Id: I2dc777ec75babb8fbb1a2dd8949636c5c05c5767
Reviewed-on: https://chromium-review.googlesource.com/754337
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>