re PR libgcj/10596 (Reference and String.intern don't work together)

re PR libgcj/10596 (Reference and String.intern don't work together)

	PR libgcj/10596:
	* include/jvm.h (_Jv_FinalizeString,
	_Jv_RegisterStringFinalizer): Declare.
	* java/lang/natString.cc (_Jv_FinalizeString): Renamed from
	unintern.
	(intern): Updated.
	(_Jv_NewStringUtf8Const): Likewise.
	* java/lang/ref/natReference.cc (finalize_referred_to_object):
	Add special case when finalizing a String.
	(in_hash): New function.
	(_Jv_RegisterStringFinalizer): Likewise.
	(maybe_add_finalize): Likewise.

From-SVN: r71915