Preparatory refactoring for zcash/librustzcash#1673 #6354

Job	Run time
Test no-Orchard on macOS	6m 8s
Slow Test Orchard on Linux	4m 18s
Test Orchard on macOS	8m 59s
Slow Test NU7 on Linux	4m 20s
Bitrot check	1m 38s
Test no-Orchard on Windows	8m 17s
Test Orchard on Windows	14m 38s
Test NU7 on Windows	14m 20s
Build target wasm32-wasi	57s
Latest build on ubuntu-latest	2m 10s
Latest build on windows-latest	4m 6s
Build target thumbv7em-none-eabihf	31s
Latest build on macOS-latest	1m 42s
Clippy (MSRV)	1m 20s
Clippy (beta)	13s
Code coverage	1h 26m 0s
Test no-Orchard on Linux	4m 47s
Test Orchard on Linux	6m 40s
Intra-doc links	2m 19s
Test NU7 on Linux	6m 37s
Rustfmt	13s
protobuf consistency	1m 5s
UUID validity	3s
Check ZFuture build on Linux	27s
Check ZFuture build on macOS	49s
Check ZFuture build on Windows	2m 42s
Required status checks have passed	1s
	3h 5m 20s

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