Add operator<< for printing some dispatcher structs

When working on dispatcher code, it's very convenient to be able to
quickly print some of the dispatcher structs, like TouchState,
TouchedWindow, etc. Add operator<< to some of these structs in this CL.

This removes the need to memorize the specific function that needs to be
called, like "dump", "getDescription", etc.

Bug: 211379801
Test: none
Change-Id: I663b217a3449daa34476ac6f28f188cdf0618278