Scrollable inline keyboard suggestions

Inlined keyboard suggestions are provided by the OS while
hosted by the keyboard. The clicks are detected by the OS
trusted code to release the data. Not all suggestions may
fit on the keyboard suggestion strip and the user may need
to scroll. To support this we are delegating the touch
event stream to the keyboard window as soon as the OS
detects that the user is not clicking, i.e. after a pointer
went down and moved more than the touch slop.

Bug:146535667

Test: atest CtsAutofillTestCases
      atest inputflinger_tests
      atest com.android.server.wm.DragDropControllerTests
      atest android.server.wm.DragDropTest
      atest android.server.wm.CrossAppDragAndDropTests

      added dedicated tests to inputflinger_tests

Change-Id: Iefb732f70a7b593b31ab2f323b0c277e3819f7b7