Warning in build.properties will be errors when they run
in the tycho build, like this:
```
Error: Failed to execute goal org.eclipse.tycho:tycho-packaging-plugin:2.7.5:package-plugin
(default-package-plugin) on project org.eclipse.cdt.core.tests:
/home/runner/work/cdt/cdt/core/org.eclipse.cdt.core.tests/build.properties:
bin.includes value(s) [test.xml] do not match any files. -> [Help 1]
```
So make them errors in the workspace so that the issue is
detected before push.
Some build.properties issues don't affect the build, but
are still indicative of a problem.
