swr: [rasterizer] Add rdtsc buckets support for shaders

swr: [rasterizer] Add rdtsc buckets support for shaders

Pass pointer to core buckets mgr back to sim layer.

Add support for RDTSC_START/RDTSC_STOP macros in the builder.

Each unique shader now has a unique bucket associated with it,
enabling more detailed reporting at the shader level. Currently
due to some llvm issue with thread local storage, 64bit runs require
single threaded mode.