Remove icmp BPF builtin #140

Job	Run time
abi-dump-setup	55s
Test lld / Lit Tests (ubuntu-latest)	10m 37s
Build lldb / Lit Tests (ubuntu-latest)	25m 55s
Test llvm,clang,libclc / Lit Tests (ubuntu-latest)	43m 42s
Test lld / Lit Tests (windows-2019)	1m 47s
Build lldb / Lit Tests (windows-2019)	1m 30s
Test llvm,clang,libclc / Lit Tests (windows-2019)	1m 32s
Test llvm,clang,libclc / Lit Tests (macOS-latest)	2h 16m 50s
Build lldb / Lit Tests (macOS-latest)	29m 0s
Test lld / Lit Tests (macOS-latest)	24m 45s
abi-dump (build-baseline)	31m 28s
abi-dump (build-latest)	32m 33s
abi-compare	29s
	5h 41m 3s

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