Tentative fix for aidl import issue

Fix issue when aidl generation doesn't use the right type when
it is a suffix of a pre-declared type.

eg. android.location.Location and foo.android.location.Location. The
aidl generation will never use foo.android.location.Location.

The tentative fix reverses the order in which Namespace.Search iterates
through the known types.

A better fix would be to annotate the types that are declared in the
aidl import statements to be prioritary in Namespace.Search. Lmk if I
you agree with this approach and think that this is worth the work.
Thanks!

Change-Id: I97dd1a1d417075accf1d61f9aba5aba3dea175c6