freedreno/ir3: Add a bunch more tests for cat6 opcodes.

freedreno/ir3: Add a bunch more tests for cat6 opcodes.

This started with making note of some ldp/stp instructions from the blob
and how we differ from them.  In the process of fixing it, I accidentally
modified behavior of other opcodes, and the other instructions listed will
keep us from doing that.  I also dropped an old stl test that looks like I
took from after a shader 'end' instruction.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5815>