TST: fftpack: remove check of successful overwrite

The overwrite may not happen if f2py decides to make copies e.g. due to
aligment. The purpose of the test is to check only that no spurious
overwrites occur.
(cherry picked from commit daf766d2926376aa5f543af8495ad9817d8863e6)
BUG: fixed integer division issue in ODR.set_iprint.

Backport of gh-2924.

Fixed integer division in indices.

Included a call to set_iprint in TestODR.test_explicit

Fixed typo
TST: fix spurious test failure in linalg.  Closes gh-2945.