Implicitly clear on incomplete keyboard input

Bug: 22931305

When the calculator is in result mode, cause a typed function name to
clear the display, just as touching the function on the screen would.

Change-Id: I77c69737a571ad8d2e6396fa3f34d5ada324fee4
(cherry picked from commit 5d79d10734b45133be7753955afd9e5edec58a1d)
1 file changed