Remove use of compiled invoke stubs from portable.

Now the invoke stubs can be safely removed. Tested and working on ARM,
basic testing done on x86/MIPS, but portable is currently broken for them
even without the change.

Change-Id: Ib73f2b7aa9d81f5f0e1e817d16b9bec464c5a5aa
diff --git a/src/thread.cc b/src/thread.cc
index a85d22a..28a01bc 100644
--- a/src/thread.cc
+++ b/src/thread.cc
@@ -164,10 +164,9 @@
     mirror::AbstractMethod* m =
         receiver->GetClass()->FindVirtualMethodForVirtualOrInterface(soa.DecodeMethod(mid));
     JValue result;
-    JValue float_result;
     ArgArray arg_array(NULL, 0);
     arg_array.Append(reinterpret_cast<uint32_t>(receiver));
-    m->Invoke(self, arg_array.GetArray(), arg_array.GetNumBytes(), &result, &float_result);
+    m->Invoke(self, arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V');
   }
   // Detach and delete self.
   Runtime::Current()->GetThreadList()->Unregister(self);