Implement getting of 64-bit locals (double, long).

Also implement the JDWP "GetClassLoader" request, used by jswat's "classes"
command.

Also implement the JDWP "exit" request, tested with jswat's "shutdown".

Change-Id: Ic8424a332151242211d8a772721deb3199b24682
diff --git a/src/object.h b/src/object.h
index 85542d2..82cd0a3 100644
--- a/src/object.h
+++ b/src/object.h
@@ -1583,7 +1583,7 @@
     SetField32(OFFSET_OF_OBJECT_MEMBER(Class, super_class_type_idx_), new_super_class_idx, false);
   }
 
-  const ClassLoader* GetClassLoader() const;
+  ClassLoader* GetClassLoader() const;
 
   void SetClassLoader(const ClassLoader* new_cl);
 
@@ -1949,7 +1949,7 @@
   String* name_;  // TODO initialize
 
   // defining class loader, or NULL for the "bootstrap" system loader
-  const ClassLoader* class_loader_;
+  ClassLoader* class_loader_;
 
   // For array classes, the component class object for instanceof/checkcast
   // (for String[][][], this will be String[][]). NULL for non-array classes.