This patch adds initial support for AMD Zen 6 architecture (znver6):
- Added znver6 CPU target recognition in Clang and LLVM
- Updated compiler-rt CPU model detection for znver6
- Added znver6 to target parser and host CPU detection
- Added znver6 to various optimizer tests
znver6 features: FP16, AVXVNNIINT8, AVXNECONVERT, AVXIFMA (without BMM).