CursorInputMapper: Populate axes in navigation mode

A bug in CursorInputMapper resulted in the output of the mapper always
reporting a value of 0 for the x and y axes when it was in navigation
mode. This was not caught by the tests because the tests used an epsilon
of 1.0, while expecting events with magnitudes of around 0.1667. The
relatively large epsilon meant the test was always passing.

Here, we fix the bug, and update the tests for CursorInputMapper to use
a smaller epsilon.

Bug: 179274888
Test: atest inputflinger_tests
Change-Id: I406486069aa42f713b8390364bcdd47ec5b33b82