mesa: Report GL_SHADER_BINARY_FORMAT_SPIR_V as supported
As described in #7644 (closed), GL_SHADER_BINARY_FORMAT_SPIR_V
should be listed in GL_SHADER_BINARY_FORMATS
for GL implementations supporting GL_ARB_gl_spirv.
I'm not too familiar with the infrastructure around glGet*, so I'm not 100% sure whether the placement of NUM_SHADER_BINARY_FORMATS
and SHADER_BINARY_FORMATS
could be better, or if using NO_EXTRA
is correct here.
I'd be happy for comments if I can improve something there.