MAINT: remove deprecated instruments from tests

[jklenzing]

Is your feature request related to a problem? Please describe.
pysat 3.2.0 will drop 3 instruments that are used in the tests here. They either represent redundancy or features that will no longer be supported.

Describe the solution you'd like

• Drop tests for pysat_testing2d (no longer supported)
• Replace pysat_testing_xarray with pysat_ndtesting
• Replace pysat_testing_2dxarray with pysat_ndtesting

Describe alternatives you've considered
😴

Additional context
There may need to be some updates at pysat to make pysat_ndtesing a suitable replacement for pysat_testing_xarray needed to update tests so that profile size is not hard wired