Fix a key repeating bug. (DO NOT MERGE)

This change fixes a bug in the dispatcher where the window manager
policy would incorrectly receive a key repeat count of 0 in the case
where the key repeat was generated by the hardware or driver.
Long-press on HOME was broken as a result.

Repeating keys could also get stuck down.

Bug: 3159581
Bug: 3208156
Change-Id: I1145487cfcc41a7850dba4cafc63c4a5951ace5b