[test] Work around Android linker warning in test output

Bug: chromium:1099623
Change-Id: I88ab0cec0ba505dcfc77d2f5eb271321633ca3be
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2270165Reviewed-by: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68556}

tools/testrunner/outproc/base.py

@@ -193,6 +193,8 @@ class ExpectedOutProc(OutProc):
             line.startswith('**') or
             line.startswith('ANDROID') or
             line.startswith('###') or
+            # TODO(machenbach): Android linker warning.
+            line.startswith('WARNING: linker:') or
             # FIXME(machenbach): The test driver shouldn't try to use slow
             # asserts if they weren't compiled. This fails in optdebug=2.
             line == 'Warning: unknown flag --enable-slow-asserts.' or