Remove GraalVM internal class usage for JDK11 compatibility

[gwenneg]

Fixes #5682

[gwenneg]

This PR is a first step towards our GraalVM compatibility with JDK 11. I only had time to check it doesn't break the Quarkus build with JDK 8 last night, I will run the test with JDK 11 tonight.

It fixes the runtime initialization for sure, but the runtime reinitialization will probably fail during the native image generation since the RuntimeClassInitializationSupport class is still used in our generated bytecode (but it was removed from the Quarkus sources).

One thing I've started investigating is the possibility to stop reinitializing classes at runtime since it was a hack (according to a comment in our sources) from the beginning and GraalVM deprecated the API option: https://github.com/oracle/graal/blob/e0cb8e79782f4d863180c9ce84519c634922cbfe/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/classinitialization/ClassInitializationFeature.java#L124-L126. We only have a few cases where this "hack" is used in Quarkus.

[gwenneg]

The current code of this PR seems to be enough to fix the GraalVM internal class usage in Quarkus, which is a requirement for the Quarkus sources compatibility with GraalVM 19.3.0, JDK 11 edition. It was successfully tested with several native builds including quarkus-integration-test-kafka which is one of the few builds reinitializing classes at runtime. The tests were run using both the quay.io/quarkus/ubi-quarkus-native-image:19.3.0-java11 image and a local GraalVM 19.3.0 CE installation.

Since it is not breaking anything in the master (JDK 8) CI, I think it is safe to be merged now even if the GraalVM 19.3.0 support is not ready yet (see #5358).

If you want to test Quarkus with GraalVM 19.3.0 and JDK 11 before this PR is merged, you will need to checkout #5358 and then cherry-pick the commit from this PR. I'll rebase #5358 on master as soon as this one is merged.

I didn't spend much time investigating the possibility to stop reinitializing classes at runtime, but that's still on my TODO list and will be treated in another PR if there's something to merge eventually.

cc @bobmcwhirter, @dmlloyd, @Sanne

[gwenneg]

Thanks for reviewing this @dmlloyd.