[DFT] Split descriptor tests that do not need a device

[Rbiessy]

Description

This builds on #259.

Some descriptor tests do not need a device as we do not need to commit
them. This follows from the discussion in #261 (comment).
The descriptor is now only committed to check that the commit status is
updated.

Checklist

All Submissions

• Do all unit tests pass locally? Attach a log.
• Have you formatted the code using clang-format?

New interfaces

• Have you provided motivation for adding a new feature as part of RFC and
  it was accepted? # (RFC)
• What version of oneAPI spec the interface is targeted?
• Complete New features checklist

New features

• Have you provided motivation for adding a new feature?
• Have you added relevant tests?

Bug fixes

• Have you added relevant regression tests?
• Have you included information on how to reproduce the issue (either in a
  GitHub issue or in this PR)?

[Rbiessy]

DFT descriptor test log: test_dft_descriptor_log.txt

[FMarno]

LGTM

[hjabird]

Looks good to me.

[Rbiessy]

I have fixed the conflicts. Logs for the tests running with the CPU and GPU backends are attached: log_cpu.txt and log_gpu.txt.
FYI We have found unrelated issues when both backends are enabled and the tests using the compile time dispatch are run. CMake is currently linking with both backends so a test could be run on a gpu device with the CPU backend and fail. We are planning to fix this in a separate PR.