Refactor to replace FloatPoint by vec2

Using FloatPoint requires unnecessory conversion between vec2 and
FloatPoint, which is inefficient.
This CL replaces FloatPoint by vec2 everywhere.

Test: atest inputflinger_tests
Bug: 245989146
Flag: EXEMPT refactor
Change-Id: I61e64e43f6bbe643eb22e758a2934294037d8a5b
8 files changed