[JVMCI] non-default installed code must be marked as in_use

JDK-8226705 propagated calls to nmethod::mark_in_use to the cases where an nmethod is associated with a Method but left out a call in the case where an nmethod is created but is not directly associated with a method. The exposes a race where an nmethod can start to be reclaimed before it's even been associated with the InstalledCode object leading to a crash.