[Morello] Fix purecap Q register COPY when NEON is disabled

When NEON is disabled, we were up using non-C64 loads/stores for the COPY.
Fix this by updating AArch64InstrInfo::copyPhysReg().
28 jobs for !201 with build-with-neon-disabled in 274 minutes and 31 seconds (queued for 8 seconds)
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