Create new input targets for hover events

Hover events don't need to reuse the existing input targets in order to
lump events with some pointers into others.

It's possible that we need to send the same pointer as both
DISPATCH_AS_HOVER_EXIT and as DISPATCH_AS_HOVER_ENTER from the
dispatcher for the same input channel.

This is the case when we are hovering over two windows with the same
input token. Since the windows may have different transforms, we should
re-start the hovering gesture.

Bug: 263319225
Test: m inputflinger_tests && $ANDROID_HOST_OUT/nativetest64/inputflinger_tests/inputflinger_tests
Change-Id: I2bd90c9893183c0526128b124b983654e0e6a37c