Add "Instant apps" filter to app listing

Bug: 35098444
Test: new test added in ApplicationsStateTest.java ; run it by doing the
following commands:
 make SettingsLibTests -j40
 adb install -r $OUT/data/app/SettingsLibTests/SettingsLibTests.apk
 adb shell am instrument -w com.android.settingslib

In Settings->Apps&Notifications->Apps, the list of filters before this CL is:

 All | Enabled | Disabled

With this CL, the filter list becomes:

 All apps | Installed apps | Disabled apps | Instant apps

Change-Id: Ia2ec099f758901839a2aa84fe155ae032990092f