[X86] matchUnaryShuffle - add support for matching 512-bit extension patterns. (#127643)
Handles both BWI and non-BWI cases (skips PMOV*XBW without BWI).
The vector-interleaved-store-i8-stride-8.ll VPTERNLOG diffs are due to
better value tracking now recognizing the zero-extension patterns where
before it was any-extension