[GR-70676] NI-based libjvm shared library.

[graalvmbot]

This PR add a new NI macro option that allows to build a NI-based libjvm.so implementation.

Building with native-image --macro:jvm-library provides the library in

$GRAALVM_HOME/lib/svm

This conveniently allows us to use it with -XXaltjvm=svm, e.g.

$GRAALVM_HOME/bin/java -XXaltjvm=svm -cp hello HelloWorld

The Java launcher passes any system properties or runtime image options down to libjvm.so.
I.e. java -XXaltjvm=svm -XX:+InterpreterTrace -cp ... does what you would expect and runs Crema with interpreter tracing enabled.

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Additionally other related fixes are contained in this PR:

• Provide a workaround for Crema loaded classes not being visible/callable via JNI (see GR-71358)
• Ensure all core classes have the null-loader at image runtime (like the C++ based VM implementation classes in HotSpot)
• Allow libjvm.so to use the system property value for java.home at runtime (needed for JRT filesystem access to $JAVA_HOME/lib/modules)
• Use of ImageName and ImagePath (in native-image.properties) will no more cause misleading warnings in build output