mesa: Prioritize checking for GLES2's uniform transpose error.

mesa: Prioritize checking for GLES2's uniform transpose error.

The negative API tests ask to transpose a non-matrix uniform, and expect
the transpose error rather than the non-matrix error.  This may be a test
bug about ambiguous results, but since every other driver is presumably
doing this too, just follow along.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Andreas Baierl <ichgeh@imkreisrum.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12924>