[Piglit] [RFC 0/4] Extend shader_runner to cover compile failure/success

[Dylan Baker]

This series adds a little bit of code to shader_runner to cover compile
failure and success cases, basically what GLSL parser test covers.

The reason for this is that shader_runner parsers it's own GL
requirements and testing parameters, while glslparsertest requires the
python layer to parse it's config and pass it back as command line
arguments.

I had originally planned to just fix glslparsertest, but after Ken
noticed that no one had turned on compute and tess support in
glslparsertest I realized it was just another big pile of boilerplate
with different syntax. Having a single tool with a single syntax made
more sense.

This series includes a patch for gen_extensions_defined, which is a POC
patch to show how this works, and that it does.