Remove InApexModules

The only use of InApexModules was a container check that verified that
apexes didn't depend on non-stubs modules from outside the apex.  Switch
it to InApexVariants for now, although that will also need to be removed.

Bug: 372543712
Test: builds
Change-Id: I822e982e3e8767dc251c8341de9f40373982c6ed