The 24_iterators/ostream_iterator/1.cc test uses VERIFY and so is
obviously meant to have been run, not just compiled.
* testsuite/23_containers/unordered_set/allocator/ext_ptr.cc: Add
comment explaining multiple dg-do directives.
* testsuite/24_iterators/ostream_iterator/1.cc: Fix do-do directive
so test is run as well as compiled.
