Forte::register_stub() should be called only when the JVm is being instrumented by Forte (aka "Oracle Developer Studio")

https://www.oracle.com/tools/developerstudio/downloads/developer-studio-jsp.html

We currently always format the name of generated stubs and call Forte::register_stub(), which usually does nothing.

Example:

https://github.com/openjdk/jdk/blob/35387d5cb6aa9e59d62b8e1b137b53ec88521310/src/hotspot/share/runtime/sharedRuntime.cpp#L2686

We should check if Forte is enabled before fomatting the name.