So that there will be one instance of static thread synchronization variables
in AndroidWindow.
Previously there was one instance in lib_angle_deqp_gles2_tests__library
and one in libangle_deqp_libgles2, resulting in AndroidWindow::initialize
waiting forever.

BUG=angleproject:1471

Change-Id: Ia529c91e34960eb352730c1bb89a91ce6336c8a0
Reviewed-on: https://chromium-review.googlesource.com/368983
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>