This allows to have a different rule to generate the source.properties
based on the templates and place them in a directory that depends on
the current target CPU ABI. In turn this prevents the build from
mixing different source.props when building different targets.
Change-Id: I4a1d9f47426c94f376947ddae8be9f5549331616
Conflicts:
build/sdk-android-arm64-v8a.atree
build/sdk-android-x86.atree
build/sdk-android-x86_64.atree
sys-img/images_arm64-v8a_source.prop_template
sys-img/images_x86_64_source.prop_template
