fixes #22680 Nim zero clear an object inherits C++ imported class when a proc return it (#22684)

tests/cpp/t22680.nim

@@ -0,0 +1,50 @@
+discard """
+  cmd: "nim cpp $file"
+  output:'''
+cppNZ.x = 123
+cppNZInit.x = 123
+inheritCpp.x = 123
+inheritCppInit.x = 123
+inheritCppCtor.x = 123
+'''
+"""
+import std/sugar
+
+{.emit:"""/*TYPESECTION*/
+struct CppNonZero {
+  int x = 123;
+};
+""".}
+
+type
+  CppNonZero {.importcpp, inheritable.} = object
+    x: cint
+
+  InheritCpp = object of CppNonZero
+
+proc initCppNonZero: CppNonZero =
+  CppNonZero()
+
+proc initInheritCpp: InheritCpp =
+  InheritCpp()
+
+proc ctorInheritCpp: InheritCpp {.constructor.} =
+  discard
+
+proc main =
+  var cppNZ: CppNonZero
+  dump cppNZ.x
+
+  var cppNZInit = initCppNonZero()
+  dump cppNZInit.x
+
+  var inheritCpp: InheritCpp
+  dump inheritCpp.x
+
+  var inheritCppInit = initInheritCpp()
+  dump inheritCppInit.x
+
+  var inheritCppCtor = ctorInheritCpp()
+  dump inheritCppCtor.x
+
+main()