Separated Receiver and Window for input tests

This will allow for testing of multiple windows with the same receiver.
Also added the ability to send a vector of points for touch events to
prepare for tests with multiple points.

Test: /data/nativetest64/inputflinger_tests/inputflinger_tests
Bug: 140756730
Change-Id: I0c5d75ba1aa57233b4e82a4e97f2a661c8dff018