JIT

GH-140479: Update JIT builds to use LLVM 21 #4278

Job	Run time
Interpreter (Debug)	9m 53s
Free-Threaded (Debug) (21)	16m 5s
JIT without optimizations (Debug) (21)	12m 50s
JIT with tail calling interpreter (21)	3m 25s
aarch64-pc-windows-msvc/msvc (Debug)	23m 31s
x86_64-pc-windows-msvc/msvc (Debug)	20m 24s
x86_64-pc-windows-msvc/msvc (Release)	12m 10s
x86_64-apple-darwin/clang (Debug)	30m 26s
x86_64-apple-darwin/clang (Release)	23m 14s
aarch64-apple-darwin/clang (Release)	10m 23s
i686-pc-windows-msvc/msvc (Release)	12m 3s
x86_64-unknown-linux-gnu/gcc (Debug)	11m 11s
aarch64-unknown-linux-gnu/gcc (Release)	5m 38s
aarch64-pc-windows-msvc/msvc (Release)	17m 0s
aarch64-unknown-linux-gnu/gcc (Debug)	24m 30s
x86_64-unknown-linux-gnu/gcc (Release)	6m 50s
i686-pc-windows-msvc/msvc (Debug)	21m 54s
aarch64-apple-darwin/clang (Debug)	12m 0s
	4h 33m 27s

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