hdf5_msb

[svn-r12430] Purpose:
testing feature

Description:
HDF5 Test Express change; now accepts values 0 to 3.

Solution:
As explained in the RFC and documented in the code, there are now four
levels of "express-ness", 0 (no limit) to 3 (1 min limit).
It is now up to test writers to take advantage of the various levels
to tune their tests' run times.

Platforms tested:
mir (minor change)