JIT

gh-143667: Specialize FOR_ITER for dict.items(), and scalar replace the pair in the JIT #4944

Job	Run time
Interpreter (Debug)	11m 0s
Free-Threaded (Debug) (21)	17m 10s
JIT with tail calling interpreter (21)	4m 18s
JIT without optimizations (Debug) (21)	13m 0s
i686-pc-windows-msvc/msvc (Debug)	25m 30s
aarch64-pc-windows-msvc/msvc (Release)	18m 31s
aarch64-pc-windows-msvc/msvc (Debug)	23m 34s
x86_64-pc-windows-msvc/msvc (Debug)	26m 0s
x86_64-apple-darwin/clang (Debug)	25m 29s
x86_64-pc-windows-msvc/msvc (Release)	13m 41s
i686-pc-windows-msvc/msvc (Release)	14m 16s
x86_64-unknown-linux-gnu/gcc (Debug)	12m 58s
x86_64-apple-darwin/clang (Release)	20m 24s
x86_64-unknown-linux-gnu/gcc (Release)	8m 20s
aarch64-apple-darwin/clang (Release)	12m 10s
aarch64-apple-darwin/clang (Debug)	11m 37s
aarch64-unknown-linux-gnu/gcc (Release)	6m 42s
aarch64-unknown-linux-gnu/gcc (Debug)	8m 33s
	4h 33m 13s

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