[9/n Dispatcher refactor] Move computeTouchOcclusionInfo to WindowInfos

In this CL we
1. Moves computeTouchOcclusionInfo to  WindowInfo subclass.
2. Moves dumpWindowForTouchOcclusion to ananymous namespace.
3. Move subclass definitions before all private functions.

Bug: 367661487
Bug: 245989146
Test: atest inputflinger_tests
Flag: EXEMPT refactor
Change-Id: Ie41c0381adda2629fa1ce34499b061df76c3a14f