Remove dead code and some unused parameters

Found with CLion inspections

src/V3Clock.cpp

@@ -47,9 +47,6 @@ private:
     //  AstVarScope::user1p()   -> AstVarScope*.  Temporary signal that was created.
     AstUser1InUse m_inuser1;
 
-    // TYPES
-    enum { DOUBLE_OR_RATE = 10 };  // How many | per ||, Determined experimentally as best
-
     // STATE
     AstNodeModule* m_modp;  // Current module
     AstTopScope* m_topScopep;  // Current top scope