Remove isSolana flag #204

Job	Run time
abi-dump-setup	1m 23s
Test llvm,clang,libclc / Lit Tests (ubuntu-latest)	45m 53s
Build lldb / Lit Tests (ubuntu-latest)	21m 19s
Test llvm,clang,libclc / Lit Tests (windows-2019)	1m 54s
Test lld / Lit Tests (ubuntu-latest)	9m 18s
Build lldb / Lit Tests (windows-2019)	1m 55s
Test llvm,clang,libclc / Lit Tests (macOS-latest)	1h 1m 7s
Test lld / Lit Tests (windows-2019)	2m 26s
Build lldb / Lit Tests (macOS-latest)	16m 30s
Test lld / Lit Tests (macOS-latest)	10m 10s
abi-dump (build-baseline)	32m 11s
abi-dump (build-latest)	33m 2s
abi-compare	29s
	3h 57m 37s

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