Make file_contexts as "android:path" property

Till now, file_contexts has been treated differently that other input
src files. Now it is tagged as `android:"path"` because it is.

Bug: 144732805
Test: m
Change-Id: Ie35cf0274c5b203b35a994bfea693226c50892f3
1 file changed
tree: 7c181372122dd06f552fdade8fd4a7e50e211de0
  1. apex/
  2. Android.bp