D3D11 can only mask 8 bits of a stencil reference value, so the
upper bits are ignored. GL, however, expects the reference value
to be able to scale to 32-bits.

We will expect to fail certain edge cases where the reference value,
and mask, both use particular 9+ bit values.

Change-Id: I8c7451270d9e40310f4154955d38e51bbf7de4df
Reviewed-on: https://chromium-review.googlesource.com/181555Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>