refactor(@angular/build): optimize vitest in-memory file loading #2491

Job	Run time
list	26s
workflow (devkit-core-tests-rerun)	1m 18s
workflow (build-cli)	1m 40s
workflow (modules-builder-tests)	1m 54s
workflow (devkit-core-tests)	1m 26s
workflow (build-unit-tests)	2m 25s
	9m 9s

Provide feedback