[5/n InputDispatcher refactor] Move findTouchedSpyWindowsAt to DispatcherWindowInfo

Move findTouchedSpyWindowsAt to DispatcherWindowInfo as it operates
only on WindowInfo.

This Cl also makes windowHasTouchingPointers and
findTouchStateWindowAndDisplay static as they are used by
findTouchedSpyWindowsAt.

Bug: 367661487
Bug: 245989146
Test: atest inputflinger_tests
Flag: EXEMPT refactor
Change-Id: Id9fdcb21e4f7df068ac6b5250066648d046159e0