feat(phl): add `simplify if` tactic #4712

Job	Run time
EasyCrypt compilation (opam)	1m 20s
Fetch EasyCrypt External Projects Matrix	3s
EasyCrypt compilation (nix)	2m 23s
Check EasyCrypt Libraries (stdlib)	5m 8s
Check EasyCrypt External Projects (sha3, https://gitlab.com/easycrypt/sha3, next, ., config/tests...	12m 48s
Check EasyCrypt External Projects (cryptobox, https://gitlab.com/fdupress/ec-cryptobox, next, ., ...	2m 19s
Check EasyCrypt External Projects (xsalsa20, https://gitlab.com/fdupress/ec-xsalsa, ec-main, ., c...	1m 53s
Check EasyCrypt External Projects (jasmin-eclib, https://github.com/jasmin-lang/jasmin, main, ecl...	2m 7s
Check EasyCrypt Libraries (examples)	4m 16s
Check EasyCrypt External Projects (sphincsplus, https://github.com/MM45/FV-SPHINCSPLUS-EC, master...	14m 57s
Check EasyCrypt External Projects (xmss-security, https://github.com/formosa-crypto/formosa-xmss,...	7m 41s
Check EasyCrypt Libraries (unit)	2m 20s
Check EasyCrypt External Projects (set-status)	2s
Notification	7s
	57m 24s

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