mapping-tester fixes for errors caused by conservative mappings

[FabioTucciarone]

Main changes of this PR

This PR aims to fix some small problems in the mapping-tester concerning conservative mappings.

• incorrect configuration causing crash
• incorrect reading of timing data causing null entries

Description of the errors fixed by this PR

Executing a conservative mapping using the current config-template.xml causes the following error:

---[preCICE:B:0] (cplscheme::CouplingSchemeConfiguration in checkSubstepExchangeWaveformDegree) WARNING : You defined <exchange data="Data" ... to="A" /> in the <coupling-scheme:... />, but <participant name="A"> has no corresponding <read-data name="Data" ... />. Usually this means that there is an error in your configuration.---[preCICE:A:0] (cplscheme::CouplingSchemeConfiguration in checkSubstepExchangeWaveformDegree) WARNING : You defined <exchange data="Data" ... to="A" /> in the <coupling-scheme:... />, but <participant name="A"> has no corresponding <read-data name="Data" ... />. Usually this means that there is an error in your configuration.

---[preCICE:B:0] (cplscheme::BaseCouplingScheme in checkCouplingDataAvailable) ERROR : Data Data on mesh B-Mesh doesn't contain any samples while initializing a coupling scheme of participant B. There are two common configuration issues that may cause this. Either, make sure participant B specifies data Data to be written using tag <write-data mesh="B-Mesh" data="Data"/>. Or ensure participant B defines a mapping to mesh B-Mesh from a mesh using data Data.
terminate called after throwing an instance of 'precice::Error'

This is caused by a small error in the configuration of the coupling scheme.

Using the gatherstats.py script with a fix for the previous problem applied as follows:

python3 "${MAPPING_TESTER}"/gatherstats.py --outdir "${RUN_LOCATION}" --file statistics.csv

causes the entries for mapDataTime and computeMappingTime to be empty:

┌────────────┬────────────────┬─────────────┬────────────────────┐
│ globalTime ┆ initializeTime ┆ mapDataTime ┆ computeMappingTime │
│ ---        ┆ ---            ┆ ---         ┆ ---                │
│ i64        ┆ i64            ┆ str         ┆ str                │
╞════════════╪════════════════╪═════════════╪════════════════════╡
│ 42064406   ┆ 6942           ┆ null        ┆ null               │
└────────────┴────────────────┴─────────────┴────────────────────┘

Author's checklist

• I used the pre-commit hook and used pre-commit run --all to apply all available hooks.
• I added a test to cover the proposed changes in our test suite.
• I updated the documentation in docs/README.md.
• I added a changelog entry in ./changelog-entries/ (create if necessary).
• I updated potential breaking changes in the tutorial precice/tutorials/aste-turbine.

[davidscn]

@FabioTucciarone can you rebase and trigger the CI again?

[davidscn]

Perfect, thanks!