Explicitly pass userId to getWindowToken

UiAutomationConnection.clearWindowContentFrameStats method currently clears
calling identity before calling mAccessibilityManager.getWindowToken. This
doesn't work properly when a call is made by a secondary user, because it
wouldn't pass a check in getWindowToken. This is now fixed by explicitly
passing ID of the calling user.

Bug: 26498396
Change-Id: I8f0cdde33e18f04adb1833c6c0d0c329de921018