Fix AIX test failure due to replacement operator delete

Fix AIX test failure due to replacement operator delete

On AIX the sized delete defined in the library will call the non-sized
delete defined in the library, not the replacement version defined in
the test file. By also replacing sized delete we make the test pass
everywhere.

	* testsuite/20_util/allocator/1.cc: Add sized delete, which fixes a
	failure on AIX.

From-SVN: r272391