Support XSLT on GraalVM Native Image--deterministic bytecode generation in XSLT

GraalVM Native Image supports loading classes at runtime if they are known during image build (class predefinition). This is achieved by the JVMTI agent that registers dynamically generated classes in a regular HotSpot run. The Native Image build uses these registered classes to embed them into the produced binary so they can be loaded at runtime. Loading at runtime is achieved by matching the unique hash of generated classes.

If the generated bytecode is unstable across runs, the generated native image can not match the hash of the runtime-generated bytecode to the pre-defined classes. The execution failure happens here:
 https://github.com/oracle/graal/blob/master/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/hub/PredefinedClassesSupport.java#L127-L131.

In XSLT the produced bytecode is unstable for the following reasons:

- Methods like ` HashMap#values` and `HashMap#keySet` result in different traversal orders of its elements yielding a different order of methods and fields.

- The default `Object#toString` includes the current memory reference of `com.sun.org.apache.xalan.internal.xsltc.compiler.Number` in the generated class.