gmxapi tests using gmx to make a .tpr needs to be quieter
In order to avoid bundling a .tpr file that is needed for testing, gmxapi is using the gmx target to run grompp at build time. This means that in
cmake -DGMX_DEVELOPER_BUILD=on that a
make all runs
gmx grompp and that writes to the terminal. I think we should not output to the terminal from make unless there's a problem.
So, we could at least run
gmx -quiet grompp. But preferably catch the terminal output and throw it away. Alternatively, work out how to call grompp as part of the test.
We should probably also not build the API tests when the cmake CROSSCOMPILING variable is true, because we can't run gmx then, either.
Clean up gmxapi testsupport output.
Silence grompp during CMake preparation of gmxapi test input data. Make
some notes that a better long term solution is necessary.