EGL_CHROMIUM_sync_control: Add initial tests.

Test the EGL_CHROMIUM_sync_control extension, which is similar to
the GLX_OML_sync_control extension:

http://www.opengl.org/registry/specs/OML/glx_sync_control.txt

The extension only defines one new function,
EGL_CHROMIUM_get_sync_values, which is equivalent to the
glXGetSyncValuesOML function.

It's difficult to test the Media Stream Counter (MSC) without the
equivalent function to get the MSC rate (glXGetMscRateOML).  The test at
least makes sure MSC and SBC increment after two SwapBuffers() calls.
UST is system-dependent, so it may behave differently on Windows, Linux,
and Apple.  The test just makes sure it increments monotonically.

The test uses Chad's new subtest infrastructure and the EGL convenience
functions from egl-util.c.

v2:
 - Remove glFinish in egl_util_run.  Tests still pass without it.
 - Fix memory leak of vinfo in create_window.
 - Make error handling code in egl_util_run more readable/verifiable.
 - Make sure test is const in egl_util_run.
 - The extension *name* should be EGL_CHROMIUM_sync_control, and the new
   *function* is called EGL_CHROMIUM_get_sync_values.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Chad Versace <chad.versace@linux.intel.com>
Cc: Rob Bradford <rob@linux.intel.com>