Fix ordering of overlays

Device overlays are passed to Soong in highest priority to lowest
priority order, but aapt2 keeps the last value provided on the
command line.  Reverse the order that overlayGlobResults are
collected.

Bug: 71595164
Test: app_test.go
Change-Id: Ibc6b8297f1548766c5c92f3be969b89736dc8dff