refactor(@angular/cli): remove unused package-tree utilities #2846

Job	Run time
list	31s
workflow (modules-builder-tests)	1m 47s
workflow (build-unit-tests)	2m 27s
workflow (devkit-core-tests-rerun)	1m 31s
workflow (devkit-core-tests)	1m 20s
workflow (build-cli)	1m 49s
	9m 25s

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