Failing tests when /tmp is not writable

**Describe the bug**
The HDF tests fail if /tmp is not writeable

**Platform**
- v1.13.1
- Not compiler dependent

I think there are three files that will create errors in this case

- test/test_usecases.sh
- bin/outputfilter.sh
- tools/test/h5repack/h5repack.sh

Each of these have a few references to /tmp as a location for temporary files. On my system, changing to /$TMP allows the tests to pass, but I am not sure if this is reliable cross-platform.