[LiveDebugValues] Delete unneeded copy constructor after D83047

It will suppress the implicitly-declared copy assignment operator in C++20.

Author: MaskRay

llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp

@@ -363,9 +363,6 @@ class DbgValueProperties {
   DbgValueProperties(const DIExpression *DIExpr, bool Indirect)
       : DIExpr(DIExpr), Indirect(Indirect) {}
 
-  DbgValueProperties(const DbgValueProperties &Cpy)
-      : DIExpr(Cpy.DIExpr), Indirect(Cpy.Indirect) {}
-
   /// Extract properties from an existing DBG_VALUE instruction.
   DbgValueProperties(const MachineInstr &MI) {
     assert(MI.isDebugValue());