Don't compile test classes when launching Quarkus Dev from Gradle

[geoand]

• Fixes: Quarkus dev cannot start when Kotlin tests do not compile #47495

[geoand]

I have no idea if this breaks anything else, nor do I know why it was done the way it was initially.

Hopefully someone from @quarkusio/devtools knows more :)

[aloubyansky]

Ideally, we'd want something similar to https://github.com/quarkusio/quarkus/pull/20991/files
Which sets failOnError = false but for Kotlin. I couldn't find a way to do that though.

[Sanne]

This looks simple and reasonable - is there a reason for it to have stalled?

[aloubyansky]

We need to attempt to compile the tests, since dev mode may need to run them.