[Piglit] start of GLSL 1.40 testing

[Kenneth Graunke]

On 03/09/2012 12:58 PM, Eric Anholt wrote:
[snip]
> - ARB_compatibility.
>
>    I'm not interested in ARB_compatibility, nor do I expect Mesa to
>    support it, so I haven't done any testing of interactions with it.

Agreed.  That said, it might be nice to flag the glslparsertests that 
make sure deprecated functionality is removed with:

// required_extensions: !GL_ARB_compatibility

which will make them "skip" should someone ever expose that extension.

(This needs my newly-posted patch:
  "glslparsertest: Allow ! in extension list to require non-support.")