Fix build warnings for x86+arm targets

This likely doesn't fix all of the issues, but it at least removes the
pages of overriding command warnings for these configurations.

Test: lunch aosp_x86_arm-eng; m nothing
Test: build-aosp_arm.ninja is identical
Test: build-aosp_arm64.ninja is identical
Change-Id: Iacdfd56d098eec08cf588c98ca00c7c7e10c6261