feat(@angular/build): add isolate option to unit-test builder #10250

Job	Run time
build	1m 6s
lint	3s
build-e2e-windows	3s
e2e-windows	1s
publish-snapshots	1s
test	1s
Browser Compatibility Tests	1s
e2e	1s
e2e-package-managers	1s
e2e-snapshots	1s
	1m 19s

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