[flang] Carry over the derived type from target in pointer remapping

When calling PointerAssociateRemapping the dynamic type information
from the target needs to be carried over to the pointer if any.

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D143717

flang/runtime/pointer.cpp

@@ -121,6 +121,13 @@ void RTNAME(PointerAssociateRemapping)(Descriptor &pointer,
                      "pointer (%zd > %zd)",
         pointer.Elements(), target.Elements());
   }
+  if (auto *pointerAddendum{pointer.Addendum()}) {
+    if (const auto *targetAddendum{target.Addendum()}) {
+      if (const auto *derived{targetAddendum->derivedType()}) {
+        pointerAddendum->set_derivedType(derived);
+      }
+    }
+  }
 }
 
 int RTNAME(PointerAllocate)(Descriptor &pointer, bool hasStat,