Performance optimizations in generatePackageInfo

In PM.generatePackageInfo, granted permissions (returned by permissionsState.
getPermissions) are only used if the package has a non-empty list of
requested permissions. Added a shortcut to handle that. In my tests
this shortcut is triggered in ~20% calls to PM.generatePackageInfo.

Also added an early continue in PermissionsState.getPermissions. Calling
hasRuntimePermission was not necessary in 90% cases.
Also changed ArraySet to be created with capacity for all mPermissions --
this is the typical scenario, previously it was going through multiple
grow operations.

Bug: 29879962
Change-Id: Ic4d8914d1c4f4df447deee2e3e3a15a2594e90ef