Reduced the number of `BOOST_CHECK_*`.

* test/unit/memory/polymorphic_allocator_run.cpp: Reduced the number of
  `BOOST_CHECK_*` because many `BOOST_CHECK_*` place an unnecessary burden
  on unit test process. In addition, many `BOOST_CHECK_*` lead to large XML
  reports, and Jenkins xUnit plug-in refuses such reports.