JIT

Support LLVM_VERSION configuration via env #13

Job	Run time
Interpreter (Debug)	9m 39s
i686-pc-windows-msvc/msvc (Debug)	23m 40s
x86_64-pc-windows-msvc/msvc (Release)	11m 28s
x86_64-pc-windows-msvc/msvc (Debug)	20m 55s
x86_64-apple-darwin/clang (Release)	19m 55s
x86_64-apple-darwin/clang (Debug)	17m 2s
aarch64-apple-darwin/clang (Release)	9m 28s
i686-pc-windows-msvc/msvc (Release)	14m 36s
aarch64-pc-windows-msvc/msvc (Release)	15m 58s
aarch64-pc-windows-msvc/msvc (Debug)	20m 42s
aarch64-apple-darwin/clang (Debug)	10m 24s
aarch64-unknown-linux-gnu/gcc (Release)	5m 57s
x86_64-unknown-linux-gnu/gcc (Release)	6m 48s
aarch64-unknown-linux-gnu/gcc (Debug)	7m 23s
x86_64-unknown-linux-gnu/gcc (Debug)	14m 18s
	3h 28m 13s

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