Support instrumentation of hidden classes

[eupp]

Currently, hidden classes cannot be instrumented by Lincheck, because we use dynamic agent attachment and class re-transformation.
However, hidden classes are not modifiable and thus cannot be redefined or re-transformed:
https://bugs.openjdk.org/browse/JDK-8230502

This poses a problem for us. Since Java 15+, lambdas in Java are compiled into hidden classes. It means that we currently cannot instrument Java lambdas on JDKs 15+.