Fix bug where path shortening breaks ColorStateLists

Android resource loader uses the file path to check if a resource is a
ColorStateList. Path shortening removed that part of the path and thus
broke the resource loader of APKs optimized with path shortening. This
cl skips path shortening for resources under "res/color/"

Test: make aapt2_tests
Bug: b/75965637

Change-Id: If94dfa398efd81522d4faed157afd35f6dabe856