strict_encoding_test

It's used only as a dev dependency in 4 crates.

Depender (with downloads and own rev deps)			strict_encoding_test version
950	10	psbt	dev	^0.9.0
230	2	lnpbp_chain	dev	^0.9.0
140	26	internet2	dev	^0.9.0
	1	lnp_node	dev	^0.9.0