JIT

GH-140479: Update JIT builds to use LLVM 21 #4281

Job	Run time
Interpreter (Debug)	10m 18s
Free-Threaded (Debug) (21)	15m 13s
JIT without optimizations (Debug) (21)	11m 17s
JIT with tail calling interpreter (21)	3m 55s
i686-pc-windows-msvc/msvc (Debug)	2m 24s
x86_64-pc-windows-msvc/msvc (Debug)	2m 43s
x86_64-apple-darwin/clang (Release)	26m 38s
x86_64-pc-windows-msvc/msvc (Release)	2m 58s
i686-pc-windows-msvc/msvc (Release)	2m 46s
x86_64-unknown-linux-gnu/gcc (Release)	7m 54s
aarch64-pc-windows-msvc/msvc (Release)	5m 43s
aarch64-pc-windows-msvc/msvc (Debug)	7m 13s
x86_64-apple-darwin/clang (Debug)	27m 11s
aarch64-apple-darwin/clang (Release)	12m 23s
aarch64-apple-darwin/clang (Debug)	21m 54s
x86_64-unknown-linux-gnu/gcc (Debug)	11m 38s
aarch64-unknown-linux-gnu/gcc (Release)	6m 1s
aarch64-unknown-linux-gnu/gcc (Debug)	7m 4s
	3h 5m 13s

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