Change 'This promise has already been verified' message from verbose to debug
(cherry picked from commit 708d24453222ed64e8e1a51bee3dce2465979e4f)
NULL-proof ScopeGet

This arised when function regarray was calling ScopeGet with a NULL pointer,
resulting in a segfault. We have as a rule agreed that this is an error on
the caller side, but since we are getting close to the release, I don't want
to risk additional segfaults due to careless callers. Either way, ScopeGet is
marked for deprecation.
(cherry picked from commit e62516455b5ea6a6a8a12ed7c09dc50de91184d4)