hdf5_ep

Incorporate additional code changes for the H5DOread_chunk patch from GE healthcare (HDFFV-9934)
Incorporate the code changes that were missing from the original patch:
(1) Additional tests in hl/test/test_dset_opt.c
(2) Fix in src/H5Dchunk.c for direct access when an entry is in chunk cache but not dirty
Tested on playtpus, ostrich, kituo, mayll, osx1010test, quail, emu.