input: don't log the whole MotionEvent in index checks

We've had a crash report where this causes infinite recursion, probably
through the following call sequence:

  operator<<(std::ostream&, const MotionEvent&)
→ MotionEvent::get(X|Y)
→ MotionEvent::getAxisValue
→ MotionEvent::getHistoricalAxisValue
→ MotionEvent::getHistoricalRawPointerCoords
→ operator<<(std::ostream&, const MotionEvent&)

It's unclear how the MotionEvent gets corrupted such that
getHistoricalRawPointerCoords is called with invalid indexes, but the
simple fix is to only log a useful subset of the whole event in these
checks.

Bug: 379368465
Test: m checkinput
Flag: EXEMPT bug fix
Change-Id: I0822f88fc7da6ba08ba6dbbab71ca5aaf78fc35d