JIT

GH-136895: Update JIT builds to use LLVM 20 #4187

Job	Run time
Interpreter (Debug)	10m 11s
Free-Threaded (Debug)	8m 48s
JIT without optimizations (Debug)	8m 46s
i686-pc-windows-msvc/msvc (Debug)	8m 48s
x86_64-pc-windows-msvc/msvc (Debug)	8m 48s
i686-pc-windows-msvc/msvc (Release)	8m 49s
x86_64-pc-windows-msvc/msvc (Release)	8m 49s
x86_64-apple-darwin/clang (Release)	8m 54s
aarch64-pc-windows-msvc/msvc (Release)	8m 48s
aarch64-pc-windows-msvc/msvc (Debug)	8m 47s
x86_64-apple-darwin/clang (Debug)	8m 56s
x86_64-unknown-linux-gnu/gcc (Release)	8m 33s
aarch64-apple-darwin/clang (Release)	8m 46s
aarch64-unknown-linux-gnu/gcc (Debug)	7m 29s
aarch64-unknown-linux-gnu/gcc (Release)	5m 54s
aarch64-apple-darwin/clang (Debug)	8m 48s
x86_64-unknown-linux-gnu/gcc (Debug)	8m 46s
	2h 26m 40s

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