revert subtype theory + syntactic sugar for cloning it #3631

Job	Run time
Fetch EasyCrypt External Projects Matrix	3s
EasyCrypt compilation (nix)	1m 17s
EasyCrypt compilation (opam)	1m 17s
Check EasyCrypt Libraries (unit)	1m 23s
Check EasyCrypt External Projects (jasmin-eclib, https://github.com/jasmin-lang/jasmin, main, ecl...	2m 2s
Check EasyCrypt Libraries (stdlib)	4m 49s
Check EasyCrypt External Projects (sha3, https://gitlab.com/easycrypt/sha3, next, ., config/tests...	12m 22s
Check EasyCrypt Libraries (examples)	3m 4s
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, master, ., co...	1m 48s
Check EasyCrypt External Projects (xmss-acai, https://github.com/MM45/FV-XMSS-EC, master, ., conf...	7m 8s
Check EasyCrypt External Projects (xmss-fsai, https://github.com/MM45/FV-XMSS-EC, master, ., conf...	6m 30s
Check EasyCrypt External Projects (sphincsplus, https://github.com/MM45/FV-SPHINCSPLUS-EC, master...	19m 27s
Check EasyCrypt External Projects (set-status)	3s
Notification	2s
	1h 3m 34s

Provide feedback