BP5 tests: Only run them if ADIOS2 has BP5

[franzpoeschel]

Fix #1257

[ax3l]

Thanks a lot!

Do you also want to update the "bp5" locations in src/IO/ADIOS/ADIOS2IOHandler.cpp?

I also looked at src/config.cpp for openPMD::getFileExtensions() - but there we only list bp right now.

[franzpoeschel]

We don't currently check for available engines in the ADIOS2 backend at all (on Windows, there's no SST, but we don't check for that)
Maybe we should do it? But if so, then that should maybe go into a different PR. Currently, there will be an ADIOS2 error if selecting an unknown engine (e.g. "This version didnt compile with…" or "Unknown engine type …")

I also looked at src/config.cpp for openPMD::getFileExtensions() - but there we only list bp right now.

Good point, this is a Todo for #1218

[ax3l]

Sounds good to me, thank you :)

[ax3l]

As discussed: BP5 patches will first land in 0.15.0