Add `muldiv_c` and `muxadd` peepopts #1561

Job	Run time
pre_job	5s
Prepare Visual Studio build	31s
WASI build	20m 6s
Build nix flake (ubuntu-latest)	11m 4s
Build nix flake (macos-latest)	6m 43s
Visual Studio build	10m 53s
	49m 22s

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