Switch to ImpulseVelocityTracker fling strategy.

The current default VelocityTrackerStrategy is lsq2,
which is using second-order least squares fits to
calculate the fling velocity. However, that strategy
has a few shortcomings, which should be fixed by the
impulse strategy.

Bug: 64680775
Bug: 35412046
Test: /data/nativetest/libinput_tests/VelocityTracker_test
(test will be fixed after this CL ends by re-recording some of the
flings that fail due to the implementation change of the
impulse strategy)

Change-Id: Ib4d70bc3c88892f01d29bc1cb8f5802ace938d45