[DebugInfo][InstrRef] Treat ORRWrr as a copy instr (#123102)

The insturction selector uses the `MachineFunction::copySalvageSSA`
function to insert `DBG_PHIs` or identify a defining instruction for a
copy-like instruction when finalizing Instruction References.

AArch64 has the ORR instruction which is a logical OR with the variants
ORRWrr which refers to a register to register variant, and ORRWrs which
is a register to a shifted register variant.

An ORRWrs where the shift amount is 0, and the zero register ($wzr) is
used is considered a copy, for example:

`$w0 = ORRWrs $wzr, killed $w3, 0`

However an ORRWrr with a zero register is not considered a copy

`$w0 = ORRWrr $wzr, killed $w3`

This causes an issue in the livedebugvalues pass because in aarch64-isel
the instruction is the ORRWrr variant, but is then changed to the ORRWrs
variant before the livedebugvalues pass.

This causes a mismatch between the two passes which leads to a crash in
the livedebugvalues pass.

This patch fixes the issue.