Templatize spreadinterp and more cleanups (#567) #432

Job	Run time
prepare	2s
Build with Pip (ubuntu-22.04, 3.8, llvm, -march=native)	1m 26s
Build with Pip (ubuntu-22.04, 3.8, llvm, -march=x86-64)	1m 18s
Build with Pip (ubuntu-22.04, 3.8, gcc, -march=native)	1m 2s
Build with Pip (ubuntu-22.04, 3.8, gcc, -march=x86-64)	1m 2s
Build with Pip (ubuntu-22.04, 3.11, llvm, -march=native)	1m 22s
Build with Pip (ubuntu-22.04, 3.11, llvm, -march=x86-64)	1m 12s
Build with Pip (ubuntu-22.04, 3.11, gcc, -march=native)	58s
Build with Pip (ubuntu-22.04, 3.11, gcc, -march=x86-64)	57s
Build with Pip (windows-2022, 3.8, msvc, /arch:AVX2)	11m 40s
Build with Pip (windows-2022, 3.8, msvc, /arch:SSE2)	12m 23s
Build with Pip (windows-2022, 3.8, llvm, /arch:AVX2)	12m 4s
Build with Pip (windows-2022, 3.8, llvm, /arch:SSE2)	12m 40s
Build with Pip (windows-2022, 3.11, msvc, /arch:AVX2)	11m 44s
Build with Pip (windows-2022, 3.11, msvc, /arch:SSE2)	11m 47s
Build with Pip (windows-2022, 3.11, llvm, /arch:AVX2)	12m 10s
Build with Pip (windows-2022, 3.11, llvm, /arch:SSE2)	11m 44s
Build with Pip (macos-13, 3.8, llvm, -march=native)	3m 11s
Build with Pip (macos-13, 3.8, llvm, -march=x86-64)	2m 47s
Build with Pip (macos-13, 3.8, gcc-14, -march=native)	1m 54s
Build with Pip (macos-13, 3.8, gcc-14, -march=x86-64)	2m 7s
Build with Pip (macos-13, 3.11, llvm, -march=native)	3m 24s
Build with Pip (macos-13, 3.11, llvm, -march=x86-64)	4m 33s
Build with Pip (macos-13, 3.11, gcc-14, -march=native)	1m 55s
Build with Pip (macos-13, 3.11, gcc-14, -march=x86-64)	2m 2s
	2h 7m 24s

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