repetitive member var in derived class (#4827)

Author: RevathiJambunathan

Source/Diagnostics/BTDiagnostics.H

@@ -176,9 +176,6 @@ private:
 
     /** Vector of lab-frame time corresponding to each snapshot */
     amrex::Vector<amrex::Real> m_t_lab;
-    /** Vector of user-defined physical region for diagnostics in lab-frame
-     *  for each back-transformed snapshot */
-    amrex::Vector<amrex::RealBox> m_snapshot_domain_lab;
     /** Vector of physical region corresponding to the buffer that spans a part
      *  of the full back-transformed snapshot */
     amrex::Vector<amrex::RealBox> m_buffer_domain_lab;