Fix minor issues in tests

[PhilMiller]

In a build with Fortran disabled, I noticed the MultiLayerParserTest failing, and that the error message had a small typo.

Changes

• Add a space and quote the named module in the error message
• Disable the test when BMI Fortran is unavailable

Testing

1. With just the source changes, the error message looks better
2. With the CMake change, the test isn't built or run

Notes

Wait until my earlier PR is merged, since this branch builds on it

Checklist

• PR has an informative and human-readable title
• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Code follows project standards (link if applicable)
• Passes all existing automated tests
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future todos are captured in comments
• Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
• Reviewers requested with the Reviewers tool ➡️