WIP: Resolve "Add more unit tests for batch operations"

Description

This MR adds more unit tests to test.F90, in particular testing the mesh_batch_dotp_* routines. Further, it adds input files to test real, complex and spinor wave functions.

The test for spinor wave functions is currently disabled for the GPU as it requires fixing the batch_ops_dotp_matrix routine (issue #307 (closed)), which will be a separate MR.

News snippet

This MR adds more unit tests to test.F90, in particular testing the mesh_batch_dotp_* routines. Further, it adds input files to test real, complex and spinor wave functions.

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.

Closes #310 (closed)