[DRAFT] Increase opportunities to gen V_PERM during dag combine

[macurtis-amd]

Addresses SWDEV-570025 - unexpected instruction generated for reg shuffle on fp8

• Teaches matchPERM to handle constant zero
• Turns some SHL, ZERO_EXTEND, and ANY_EXTEND DAGs into V_PERM

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[z1-cciauto]

PSDB Link: https://compiler-ci.amd.com/job/compiler-psdb-amd-staging/3052

[macurtis-amd]

foo.llir.txt - test file extracted from JIRA foo.without-change.s.txt - asm using /COD/LATEST foo.with-change.s.txt - asm with this change

[z1-cciauto]

PSDB Link: https://compiler-ci.amd.com/job/compiler-psdb-amd-staging/3093

[z1-cciauto]

PSDB Link: https://compiler-ci.amd.com/job/compiler-psdb-amd-staging/3180

[z1-cciauto]

PSDB Link: https://compiler-ci.amd.com/job/compiler-psdb-amd-staging/3341

[z1-cciauto]

PSDB Link: https://compiler-ci.amd.com/job/compiler-psdb-amd-staging/3351