[Mesa-dev] st/glsl_to_tgsi fp64 fixes.

[Dave Airlie]

This fixes a bunch of cases with the GLSL->TGSI convertor when
it comes to doubles.

The main areas it addresses are proper handling of doubles in arrays,
double matricies and the ARB_vertex_attrib_64bit vertex input
special double handling.

These fixes contribute to fixing the CTS test
GL41-CTS.gpu_shader_fp64.varyings
along with a bunch of piglit tests I've submitted.

Dave.