[12/n Dispatcher refactor] Introduce static DispatcherTouchState

In this CL we introduce DispatcherTouchState and move methods that
manipulate touch state into it, making them static to remove any
external dependencies.

In upcoming CLs we will gradually move touchStateByDisplay to this class
removing all direct access.

Bug: 367661487
Bug: 245989146
Test: atest inputflinger_tests
Flag: EXEMPT refactor

Change-Id: Ib32ee2929f3f172133f2092f0a01749e6eae8cc5