The test creates a worker thread which initializes EGL,
then calls EGL methods which check for thread local storage values.
This can cause a crash of the values are uninialized.

BUG=angle:488

Change-Id: Ibaffede0605c720ba9ca47910690a1334ee9e20e
Reviewed-on: https://chromium-review.googlesource.com/179130Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>