Support for an OpenGL ES version can come either through OpenGL ES,
OpenGL core or available extensions. The context creation should fail
if the requested OpenGL ES version is not supported.

BUG=angleproject:1477

TEST=angle_end2end_tests

Change-Id: I810d004a1bd62f75f162d775d3cf92c4283252a3
Reviewed-on: https://chromium-review.googlesource.com/374338Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>