hdf5_msb

Merge pull request #2144 in HDFFV/hdf5 from Merging-t_2Gio-into_hdf5_1_12 to hdf5_1_12

* commit '663d6e0118d6077b8206b69521a3909a5444c8bf':
  Merge t_2Gio test into hdf5_1_12.  This will eventually be refactored out after merging the test functionality into the testphdf5 test.
  Merge t_2Gio test into hdf5_1_12.  This will eventually be refactored out after merging the test functionality into the testphdf5 test.