WebglConformance_conformance_more_conformance_quickCheckAPI_B1 flakes ~1% of the time (twice in 200 runs on one bot)

From these two runs:
https://build.chromium.org/p/chromium.gpu/builders/Mac%2010.10%20Retina%20Release%20%28AMD%29/builds/11760/steps/webgl_conformance_tests%20on%20ATI%20GPU%20on%20Mac%20Retina%20on%20Mac-10.10/logs/stdio
https://build.chromium.org/p/chromium.gpu/builders/Mac%2010.10%20Retina%20Release%20%28AMD%29/builds/11588/steps/webgl_conformance_tests%20on%20ATI%20GPU%20on%20Mac%20Retina%20on%20Mac-10.10/logs/stdio

Relevant output:

[11452:17155:0713/094347:ERROR:gpu_watchdog_thread.cc(360)] The GPU process hung. Terminating after 10000 ms.
Received signal 11 SEGV_MAPERR 000000000000