Test for ADIOS2 Git sample

[franzpoeschel]

Add testing for the ADIOS2 example data files: openPMD/openPMD-example-datasets#14

• Test attributes
• Test content

This does not test attributes as extensively as in the HDF5 sample, since we don't need to test the entire openPMD hierarchy a second time. Hence, some but not all meshes and particles are tested.

Also, I noticed that our HDF5 sample has some wrong unitDimensions.

[ax3l]

Thanks a lot!

I added windows support and some cleanups :)

[ax3l]

Dang, I just found a bug in that data set: openPMD/openPMD-example-datasets#14 (comment)

Try to:

• determine the extend of a constant record component (particle mass/charge), it should be the same size as the non-constant records
• try to read the constant record component (mass or charge) like a non-constant one