Improve sc/ UNO API unit tests by adding a CPPUNIT_ASSERT with
NUMBER_OF_TESTS in setUp(). Makes it easier to spot a mismatch between
actual and expected number of tests (you get a cppunit message instead
of a crash without an explanation).

Change-Id: I7621d8afde3bebbf94cfc3923ad2c12e249ed4c2
Reviewed-on: https://gerrit.libreoffice.org/41829Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Jens Carl <j.carl43@gmx.de>