Double.java: More Classpath merging

* java/lang/Double.java: More Classpath merging
	(isInfinite): Don't use doubleToLongBits
	(isNaN (Object)): return v != v
	(initIDs): make native
	* java/lang/Float.java: Ditto
	(isInfinite): Don't use floatToIntBits
	(isNaN (Object)): return v != v
	* java/lang/natDouble.cc: add empty initIDs()

From-SVN: r46370

libjava/java/lang/natDouble.cc

@@ -186,3 +186,9 @@ java::lang::Double::parseDouble(jstring str)
     }
   throw new NumberFormatException;
 }
+
+void
+java::lang::Double::initIDs()
+{
+  // Not used in libgcj
+}