intel/compiler: Vectorize gl_TessLevelInner/Outer[] writes & small optimizations

This series vectorizes gl_TessLevelInner/Outer[] writes in the tessellation control shader, resulting in URB write messages which write the whole vector rather than one component at a time. There's also a patch to eliminate unnecessary bonus EOT writes, though this didn't have an effect in shader-db, and might not outside of Piglit (alas)...though it's mostly reusing code, so why not?

According to shader-db, vectorizing these outputs cut 14% of send instructions in affected shaders.