Storage integration tests: restructure to attempt to mitigate flakes #5111

Job	Run time
quickstart (macos-12, Xcode_14.2)	11m 48s
quickstart (macos-13, Xcode_15.1)	26m 3s
spm (macos-12, Xcode_14.2)	4m 54s
spm (macos-13, Xcode_15.1)	6m 7s
spm-cron	0s
storage-integration-tests (macos-12, Xcode_14.2)	26m 46s
quickstart-ftl-cron-only	0s
pod-lib-lint (ios, macos-12)	3m 41s
pod-lib-lint (ios, macos-13)	17m 40s
pod-lib-lint (tvos, macos-12)	3m 24s
pod-lib-lint (tvos, macos-13)	4m 53s
pod-lib-lint (macos, macos-12)	3m 11s
pod-lib-lint (macos, macos-13)	7m 25s
pod-lib-lint (watchos, macos-12)	3m 34s
pod-lib-lint (watchos, macos-13)	5m 43s
storage-cron-only	0s
	2h 5m 9s

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