BUG: Fix bug in np.insert when axis=-1
TST: add test for negative axis values in np.insert.
BUG: Make np.insert check for out of bounds axis arguments.

Also add test for IndexError exception when axis is out of bounds.
Merge pull request 'gh-3497'

* gh-3497:
  BUG: Make np.insert check for out of bounds axis arguments.
  TST: add test for negative axis values in np.insert.
  BUG: Fix bug in np.insert when axis=-1