Since common is shared through all ANGLE code (libANGLE/tests/samples)
this is the most general place for these utils, and will give libANGLE
access to them. We'll need them to get the current executable dir for
loading the Vulkan layers.

This also means we'll need to fix the global static variable use when
we have the ability.

BUG=angleproject:1319
BUG=chromium:677841

Change-Id: I7af61920635135b28a2f02f4a8d019ee88c9dd28
Reviewed-on: https://chromium-review.googlesource.com/425440
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>