Create PQR instruction class #214

Job	Run time
abi-dump-setup	51s
Build lldb / Lit Tests (ubuntu-latest)	26m 6s
Test lld / Lit Tests (ubuntu-latest)	11m 20s
Test llvm,clang,libclc / Lit Tests (ubuntu-latest)	47m 41s
Build lldb / Lit Tests (windows-2019)	1m 53s
Test lld / Lit Tests (windows-2019)	1m 48s
Test llvm,clang,libclc / Lit Tests (windows-2019)	1m 35s
Build lldb / Lit Tests (macOS-latest)	2h 9m 36s
Test lld / Lit Tests (macOS-latest)	1h 8m 40s
Test llvm,clang,libclc / Lit Tests (macOS-latest)	4h 2m 30s
abi-dump (build-baseline)	30m 30s
abi-dump (build-latest)	30m 37s
abi-compare	35s
	9h 53m 42s

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