mesa: Convert some asserts into STATIC_ASSERT.
mesa: Convert some asserts into STATIC_ASSERT.

Reviewed-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler