AAPT: treat "-I" with lower precedence than main APK for dumping.

This is the desired behavior if resource IDs may overlap, and also happens to
improve the behavior of:

  aapt dump -I base.apk badging feature.apk

when both APKs use the same package name with different package IDs
(base=0x7F, feature=0x80).  Previously, the final call to
DynamicRefTable::addMapping was for base.apk, and all references to 0x80 were
rewritten in DynamicRefTable::lookupResourceId to 0x7F.  After this
change resources defined in both APKs are resolved correctly.

Note that this is a bit of kludge, and APKs should use different names
to avoid conflating the package IDs.

Fixes: 67070085
Bug: 64058531
Test: manual with sample in b/67070085#comment2
Change-Id: I285adb6f44a297440b08fc7a1f9ad73c700eb9bc