CPU-only build of GMRES solver no longer tries to allocate on GPU

[shakedregev]

Description

Error messages are returned when running GMRES tests suggesting the solver is trying to access GPU memory. These are benign messages as computation is carried out to completion on a CPU device and all GPU calls are ignored, but the code should not be trying to access the the device memory in the CPU mode in the first place.

_Closes #286 _

@pelesh

Proposed changes

My changes enforce strict checks on owning gpu data. Previously this was set by default to true, which is wrong in the case of a CPU only build.

Checklist

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• All tests pass. Code tested on
  • CPU backend
  • CUDA backend
  • HIP backend
• Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
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• There are unit tests for the new code.
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• The feature branch is rebased with respect to the target branch.

Further comments

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[pelesh]

Closing in favor of #292.