Implement back-tracking when searching for attributes in XML or resource bag

Shared libraries have their package ID assigned at run-time, so some
of the guarantees we used to have about sort order of attributes in
bags or XML elements no longer hold.

This CL adds back-tracking and can jump to the nearest attribute with the
same package ID and continue searching.

This means that attributes with the same package ID must be sorted by increasing
resource ID, as was the case before.

Attributes with the same package ID must be grouped together, but the groups can
be in any order. Ex: 0x02010001, 0x02010002, 0x01010000, 0x01010010, 0x7f010032

Bug:17666947
Change-Id: I9c198bbb6ca788849aac85b6323606ea5d9550d6