Squash same ApplicationInfo's in Parcel

ApplicationInfo now automatically tries to "squash" the same instances in a
Parcel.

NOTE: This CL still does *not* optimize the package manager APIs that return a
list. e.g. PM.queryContentProviders() still return duplicate AppInfo's.
We can optimize them by making ParcelableListSlice call "allowSquashing",
but that *could* have negative side effects, so I'm not doing it in this CL.
I think we can do that for S.

Bug: 148588589
Test: atest CtsContentTestCases # except for two preexsiting failures:
- android.content.pm.cts.PackageManagerTest#testGetIcon
- android.content.pm.cts.PackageManagerTest#testGetPreferredActivities

Test: Use the debugger and make sure bindApplication() is not receiving
duplicate AppInfo's in the provider list.

Change-Id: I3ba2c047a469169340c0f75c36bdfd394bc5d627