st/mesa: check for out-of-memory in st_DrawPixels()
st/mesa: check for out-of-memory in st_DrawPixels()

Before, if make_texture() or st_create_texture_sampler_view() failed
we silently no-op'd the glDrawPixels.  Now, set GL_OUT_OF_MEMORY.
This also allows us to un-nest a bunch of code.

v2: also check if allocation of sv[1] fails, per Jose.

Reviewed-by: Jose Fonseca <61b5a29db2c0650f7c8510f93eece059c1b09320@vmware.com>
Reviewed-by: Marek Olšák <8c7344a1abdb103e79ecfd488098373070c3c70e@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler