Don't be tricky with move()

The old code was trying to be clever, and suppress multiple move() calls (since hey, what can that possibly do) ... but
1. other systems (e.g. Skia) like multiple moves() -- it means something to some of their clients
2. this code has a bug!
3. why am I trying to be tricky?

Fix:
- simplify the code
- remove the bug

the bug?
- n is the number of **verbs**, not points
- if there are more verbs than points, then we access out-of-bounds memory in m_points !!!
- its easy to have more verbs than points : move() + close() + move() == 3 verbs and 2 points

could we fix the bug?
- yes, we would use m_points.back() = a instead
- but why bother, just simplify the code

Diffs=
1a605c434 Don't be tricky with move()

.rive_head

@@ -1 +1 @@
-2cbfd265dd144e6035dce8acdd30116ccd3273a5
+1a605c434dc7862d6402c5b2c58dcffb1f0aacf5