Make aidl_mapping imports deterministic

Iterating over the all_import_dirs map is nondeterminsitic.  Use
the map to track which directorires have been seen before, but
add the new directories to the import list in the order they are
visited.

Test: m nothing && mv out/soong/build.ninja /tmp && m nothing && diff -u out/soong/build.ninja /tmp/build.ninja
Change-Id: Ie37ca0ef9aa190dac49082c34f344a0f0fbcea84
1 file changed