Add more helpful error message for unfixable problem launching tests in Eclipse

[holly-cummins]

Sort-of fixes #47656

We can't properly fix the issue in Quarkus without moving away from the model where we want test classes get loaded by the 'right' classloader in the discovery phase. The underlying problem is actually an Eclipse problem, which I've submitted an Eclipse PR for.

[geoand]

👍🏽

[quarkus-bot]

Status for workflow Quarkus CI

This is the status report for running Quarkus CI on commit 39b563d.

✅ The latest workflow run for the pull request has completed successfully.

It should be safe to merge provided you have a look at the other checks in the summary.

You can consult the Develocity build scans.

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Flaky tests - Develocity

⚙️ JVM Integration Tests - JDK 17

📦 integration-tests/opentelemetry

✖ io.quarkus.it.opentelemetry.LoggingResourceTest.testException - History

• Condition with Lambda expression in io.quarkus.it.opentelemetry.LoggingResourceTest was not fulfilled within 2 minutes. - org.awaitility.core.ConditionTimeoutException

org.awaitility.core.ConditionTimeoutException: Condition with Lambda expression in io.quarkus.it.opentelemetry.LoggingResourceTest was not fulfilled within 2 minutes.
	at org.awaitility.core.ConditionAwaiter.await(ConditionAwaiter.java:167)
	at org.awaitility.core.CallableCondition.await(CallableCondition.java:78)
	at org.awaitility.core.CallableCondition.await(CallableCondition.java:26)
	at org.awaitility.core.ConditionFactory.until(ConditionFactory.java:1160)
	at org.awaitility.core.ConditionFactory.until(ConditionFactory.java:1129)
	at io.quarkus.it.opentelemetry.LoggingResourceTest.testException(LoggingResourceTest.java:113)
	at java.base/java.lang.reflect.Method.invoke(Method.java:569)