Undefined-shift error in H5T_is_numeric_with_unusual_unused_bits

[tbeu]

Describe the bug

H5T.c:6732:20: runtime error: shift exponent 64 is too large for 32-bit type 'unsigned int'
# 0 0x8bf9cc in H5T_is_numeric_with_unusual_unused_bits hdf5/src/H5T.c:6732:20
# 1 0x790abf in H5O__dtype_decode_helper hdf5/src/H5Odtype.c:818:9
# 2 0x78af61 in H5O__dtype_decode hdf5/src/H5Odtype.c:1403:9
# 3 0x78af61 in H5O__dtype_shared_decode hdf5/src/H5Oshared.h:73:34
# 4 0x7b0c9c in H5O_msg_read_oh hdf5/src/H5Omessage.c:486:5
# 5 0x7b0904 in H5O_msg_read hdf5/src/H5Omessage.c:430:30
# 6 0x64924b in H5D__open_oid hdf5/src/H5Dint.c:1697:51
# 7 0x64924b in H5D_open hdf5/src/H5Dint.c:1501:13
# 8 0x648c1b in H5D__open_name hdf5/src/H5Dint.c:1436:25
# 9 0x9f4e2b in H5VL__native_dataset_open hdf5/src/H5VLnative_dataset.c:331:25
# 10 0x9d8848 in H5VL__dataset_open hdf5/src/H5VLcallback.c:1946:30
# 11 0x9d8669 in H5VL_dataset_open hdf5/src/H5VLcallback.c:1978:30
# 12 0x63438c in H5D__open_api_common hdf5/src/H5D.c:362:25
# 13 0x634146 in H5Dopen2 hdf5/src/H5D.c:402:22

Additional context

Reported for dded937.

[jhendersonHDF]

Thanks @tbeu, will take a look. It's likely that function can't operate in the general case without running up against undefined behavior.

[tbeu]

Fix confirmed: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=67734#c3 Thanks.