Fix erroneous pixel test failure hiding

Fixes an issue recently introduced in crrev.com/c/2446717.
Currently, we're hiding all Android pixel test failures
because we re-used the should_hide_failure variable for
determining if we should add the ignore:1 key to a test's
comparison.

Hiding a failure is a separate concept from ignoring an
image in Gold, so this CL properly splits the two again.

Change-Id: I2501ce27fd20528a8d73bd1531947145253cceed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2459573
Auto-Submit: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815186}

build/android/pylib/local/device/local_device_instrumentation_test_run.py

@@ -1058,9 +1058,13 @@ class LocalDeviceInstrumentationTestRun(
         not_final_retry = self._env.current_try + 1 != self._env.max_tries
         tryjob_but_not_final_retry =\
             not_final_retry and gold_properties.IsTryjobRun()
-        should_hide_failure =\
+        should_ignore_in_gold =\
             running_on_unsupported or tryjob_but_not_final_retry
-        if should_hide_failure:
+        # We still want to fail the test even if we're ignoring the image in
+        # Gold if we're running on a supported configuration, so
+        # should_ignore_in_gold != should_hide_failure.
+        should_hide_failure = running_on_unsupported
+        if should_ignore_in_gold:
           optional_keys['ignore'] = '1'
 
         gold_session = self._skia_gold_session_manager.GetSkiaGoldSession(