refs #9906. Create and use virtual refl instrument.

Make a very simple reflectometry instrument in memory and attach a single monitor and a single detector spectrum to it. Avoids All IO related to both data and instrument, and can be used to create tiny reflectometry workspaces.

Makes a huge difference to test speed. Only applied to ReflectometryReductionOne at this stage.
refs #9906. Ported more tests over and made faster.
Merge branch 'feature/9906_RRO_auto_unit_test' into develop