JIT

Support LLVM_VERSION configuration via env #14

Job	Run time
Interpreter (Debug)	9m 52s
i686-pc-windows-msvc/msvc (Debug)	21m 8s
x86_64-pc-windows-msvc/msvc (Release)	11m 31s
x86_64-unknown-linux-gnu/gcc (Debug)	11m 28s
x86_64-apple-darwin/clang (Debug)	21m 0s
aarch64-unknown-linux-gnu/gcc (Debug)	6m 54s
aarch64-apple-darwin/clang (Debug)	10m 14s
i686-pc-windows-msvc/msvc (Release)	12m 20s
x86_64-apple-darwin/clang (Release)	16m 44s
aarch64-unknown-linux-gnu/gcc (Release)	5m 33s
x86_64-pc-windows-msvc/msvc (Debug)	23m 31s
aarch64-apple-darwin/clang (Release)	10m 25s
aarch64-pc-windows-msvc/msvc (Debug)	23m 5s
x86_64-unknown-linux-gnu/gcc (Release)	6m 50s
aarch64-pc-windows-msvc/msvc (Release)	15m 41s
	3h 26m 16s

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