Fuzz

Merge rust-bitcoin/rust-miniscript#606: Remove more recursion from `c… #220

Job	Run time
fuzz (roundtrip_miniscript_str)	7m 26s
fuzz (roundtrip_miniscript_script)	6m 39s
fuzz (parse_descriptor)	6m 2s
fuzz (roundtrip_semantic)	7m 8s
fuzz (parse_descriptor_secret)	6m 9s
fuzz (roundtrip_descriptor)	6m 10s
fuzz (roundtrip_concrete)	6m 2s
fuzz (compile_descriptor)	7m 4s
verify-execution	13s
	52m 53s

Provide feedback