Simplify intrinsics generation tool and regenerate intrinsics list #1840

Job	Run time
build (--test-libcore)	51s
build (--std-tests)	43s
build (--mini-tests)	38s
build (--test-successful-rustc --nb-parts 2 --current-part 0)	50s
build (--test-successful-rustc --nb-parts 2 --current-part 1)	47s
success_gcc12	4s
	3m 53s

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