Revert "Increase memory available to project to 8GB" #28258

Job	Run time
build-cfg	1s
android-test-gmd-cfg	1s
build-cfg-check	1s
build (21)	20m 16s
build (35)	24m 37s
android-test-gmd-cfg-check	1s
android-test-gmd (23, aosp, nexus4)	4m 45s
android-test-gmd (30, wear, wearoslargeround)	11m 52s
android-test-gmd (34, aosp, pixel2)	4m 42s
codecov-device-test-upload (23, aosp, nexus4)	6s
codecov-device-test-upload (34, aosp, pixel2)	7s
codecov-device-test-upload (30, wear, wearoslargeround)	4s
codecov-device-coverage-upload	0s
codecov-unit-coverage-upload (21)	10s
codecov-unit-coverage-upload (35)	4s
codecov-unit-test-upload (21)	8s
codecov-unit-test-upload (35)	9s
	1h 7m 4s

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