Merge pull request #2116 in HDFFV/hdf5 from ~JSOUMAGNE/hdf5:hdf5-1_12-ref_token to hdf5_1_12
* commit '1aea46ce671daf2828ac65d0b8551b369f497922':
Fix H5VL_token_t type and fix H5VL_loc_by_token to use H5VL_token_t *
Change hdset_reg_ref_t and H5R_ref_t from arrays of unsigned char to structs containing those arrays. Encapsulating the arrays in this way makes it easier to write and think about pointers to these types, casts to/from these types, etc.
H5R: fix H5Tconv to check for null references
Remove H5VL_NATIVE_FILE_GET_FILE_ID and add H5VL_OBJECT_GET_FILE
