soong: Add tests for depending on disabled module

This will check if direct deps of android.Module type is "Enabled()".
Previously, this is checked only if a module calls VisitDeps*()
functions in GenerateAndroidBuildActions().

Most modules call VisitDeps*() in GenerateAndroidBuildActions(),
but some modules don't. For example, "apex" module calls
WalkDepsBlueprint() or VisitDirectDepsBlueprint() since it
exceptionally depends on non-android.Module modules.

Therefore, when an apex module depends on disabled(enabled:false) module,
build fails with panic, which is fixed by this change.

Test: m # runs soong tests
Change-Id: I81c5c148bbd51a253d2904690eb76ae7b6df1a0f