fix(@angular/build): safeguard Karma builder stream controller agains… #10780

Job	Run time
lint	21s
build-e2e-windows	27s
build	27s
publish-snapshots	1s
Browser Compatibility Tests	1s
test	1s
e2e-package-managers	1s
e2e	1s
e2e-snapshots	1s
e2e-windows	1s
	1m 22s

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