LocalVector: Don't error if `from` >= `count`
Vector handles this silently by returning -1, and we should do the same here.
Otherwise we get errors when calling `find()` on e.g. a LocalVector of size 0,
while `find()` is expected to always work (if the parameters are invalid then
it doesn't find anything, so -1).
Fixup to #49925.
(cherry picked from commit 7b7ccf25b67ae6b28bb99b5d54f96cc299ec6b88)