Remove snapshot flood by update all overlays in one commitment

The iteration n updates some PackageUserState instances for the
specified user. Once OverlayManagerService(OMS) changes some
PackageUserState instance, it triggers a snapshot rebuild in the
next iteration.

OMS has prepared all changes in switching users. PackageManagerService
compute all changes of PackageUserStates and then use the mutator to
modified all changes of PackageUserStates in one
commitPackageStateMutation.

Test: run perfetto.ui and follow the commands on perfetto.
    b/174206591#comment14
Test: TC="PtsConfigTestCases:com.google.android.config.pts"; \
    atest ${TC}.PixelSetupWizardOverlayTest ${TC}.ConfigTestCase

Bug: 174206591
Change-Id: I2b58b5e6164a72008c284adf05f6ff0240a5a33a