Internals: Use VL_RESTORER class to save/restore vars. No functional change intended.

src/V3Descope.cpp

@@ -226,7 +226,7 @@ private:
 
     // VISITORS
     virtual void visit(AstNodeModule* nodep) override {
-        AstNodeModule* origModp = m_modp;
+        VL_RESTORER(m_modp);
         {
             m_modp = nodep;
             m_modFuncs.clear();
@@ -234,7 +234,6 @@ private:
             iterateChildren(nodep);
             makePublicFuncWrappers();
         }
-        m_modp = origModp;
     }
     virtual void visit(AstScope* nodep) override {
         m_scopep = nodep;