The class jvmaccess::VirtualMachine took care to set a non-null
context class loader for every thread attached to the VM (especially
native threads that had not been spawned by the VM and would have a
null context class loader). However, this had performance
implications. And after the cleanup of the main class path in OOo any
code that uses the context class loader now needs to set it explicitly
etc.), so removing the code that sets the context class loader
whenever a thread is attached to the VM appears to be safe.