refactor(@angular-devkit/build-angular): remove unused utility files #9908

Job	Run time
lint	1m 52s
build	2m 8s
build-e2e-windows	2m 29s
test	2m 2s
publish-snapshots	2m 2s
Browser Compatibility Tests	2m 1s
e2e-windows (24, esbuild, 3)	1m 38s
e2e-windows (24, esbuild, 4)	1m 38s
e2e-windows (24, webpack, 4)	1m 38s
e2e-windows (24, webpack, 2)	1m 39s
e2e-windows (24, esbuild, 2)	1m 32s
e2e-windows (24, webpack, 3)	1m 31s
e2e-windows (24, webpack, 0)	1m 31s
e2e-windows (24, webpack, 5)	1m 36s
e2e-windows (24, esbuild, 1)	1m 38s
e2e-windows (24, esbuild, 5)	1m 38s
e2e-windows (24, webpack, 1)	1m 32s
e2e-windows (24, esbuild, 0)	1m 30s
e2e-package-managers	1s
e2e	1s
e2e-snapshots	1s
	31m 38s

Provide feedback