mesa: fix program resource queries for builtin variables
mesa: fix program resource queries for builtin variables

Patch fixes special cases with gl_VertexID and sets all builtin
variables locations as '-1' as specified by the extension spec.

Fixes ES 3.1 conformance test failure:
	ES31-CTS.program_interface_query.input-built-in

v2: comments + use is_gl_identifier() (Martin)

Signed-off-by: Tapani Pälli <cdcb67a5e49297de94340ca09f25994bd5e7f762@intel.com>
Reviewed-by: Martin Peres <f078f77bcd6141e84e4eefdc58402db4e0e36622@linux.intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler