Cleanup ImageTest skip conditions

Early-return with a compiler guard prevents a test from being
recorded in the skip test list log. Make sure to use the
"ANGLE_SKIP_TEST_IF" macros for AHB tests.

Bug: angleproject:40644776
Change-Id: I3e15203b8e17512ecb89abc7e53769c06b770213
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5842744
Reviewed-by: Shahbaz Youssefi <[email protected]>
Reviewed-by: Charlie Lao <[email protected]>
Commit-Queue: mohan maiya <[email protected]>