nvhpc compiler produces seg fault on execution of test with matrix array slices.

Passing a slice of cmat triggers memory errors. This is a suspected compiler bug. An intermediate routine, which still uses and array slice, seems to resolve the issue.

This commit contains the workaround patch (only used for nvhpc): https://gitlab.com/NIMRODteam/nimrod-abstract/-/commit/6b2ea838daf5533fe4a1dd51a3f772d80e46c159

This issue can be closed when the workaround is able to be removed.