Create context jars for javac invocations remotely when using the hermetic exec strategy

[baroquebobcat]

creating the z.jar files is part of the work for compiling java or scala sources. That work should also be happening in the hermetic context. With the implementation in #5999, the remote exec calls javac directly and creating the context jar happens in jvm_compile at

pants/src/python/pants/backend/jvm/tasks/jvm_compile/jvm_compile.py

Line 704 in 602445e

self._create_context_jar(ctx)

Instead of doing that work there, we'd want it to be done by the binary that's invoked by the hermetic execution. That would require a shell script or something that bundles up the class files.

[stuhood]

Whoops. Thought that this was the work that Ity did in #6094. Related... but that was for zinc.