fix(@angular/build): remove explicit test isolation configuration #2421

Job	Run time
list	21s
workflow (build-cli)	1m 38s
workflow (modules-builder-tests)	2m 4s
workflow (build-unit-tests)	2m 38s
workflow (devkit-core-tests-rerun)	1m 21s
workflow (devkit-core-tests)	1m 28s
	9m 30s

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