Avoid long timeouts for unreachable urls in glbench

When running the graphics_GLBench test behind a firewall,
the test was taking many hours due to accumulation of
timeouts for unreachable urls to check the "known bad" and
"reference image" lists.  This change keeps a cache of web
hosts that result in exceptions other than the expected 404
(not found) error and does not retry them, thus avoiding
"network unreacheable" timeouts after the first such
failure.

BUG=chromium:299280
TEST=behind firewall: test_that <machine> graphics_GLBench

Change-Id: Iaa2b786598c129ed979ee29374d33fa1dfb1027b
Reviewed-on: https://chromium-review.googlesource.com/171461
Tested-by: Paul Drews <paul.drews@intel.com>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Paul Drews <paul.drews@intel.com>
1 file changed