unpack_strategy/directory: use mv for nested unpack #30835

Job	Run time
syntax	45s
formula audit	4m 31s
cask audit	2m 22s
tap syntax	6m 9s
test default formula (Ubuntu 22.04)	1m 37s
test default formula (Ubuntu 20.04)	2m 55s
tests (online)	3m 5s
test default formula (macOS 13 x86_64)	3m 20s
update-test (Ubuntu 22.04)	24s
tests (generic OS)	2m 50s
vendored gems	37s
test default formula (macOS 15 arm64)	1m 15s
update-test (macOS)	23s
tests (Ubuntu 22.04)	3m 3s
tests (Ubuntu 20.04)	3m 4s
tests (macOS 13 x86_64)	3m 5s
tests (macOS 15 arm64)	3m 5s
	42m 30s

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