Fixes flicker seen in XC2

and wip nv thread shuffle impl

Fix for SULD.D

along with some more cleanup/oversight fixes

and more cleanup

needed for HW:AoC.

along with some other misc changes and fixes

and add some more separation in the shader for better debugability when dumped

and implement misc getters

SSBU now working

and missed a diff in emit_glsl relating to var alloc ref counting