yarn mvntest failures ignored in CI

[jglick]

In jenkinsci/workflow-cps-plugin#821 I struggled to figure out how this ever passed in CI. Turns out

mvn verify -Dtest=InjectedTest -Dmaven.test.failure.ignore

prints ESLint failures but passes anyway. https://github.com/eirslett/frontend-maven-plugin#ignoring-failure does not say where test failures would be recorded. Based on inspecting sources, they are not recorded anywhere at all, so using junit is not enough. I think this mojo parameter needs to be disabled in the POM so that maven.test.failure.ignore applies only to Surefire.