fixes #19401; fixes #19402; rework Forward declaration and finalizer for ORC (#20295)

* fixes #19401; fixes #19402; rework Forward declaration and finalizer for ORC

* add more tests

* give it a name

* make more tests

* fixes tests

* hidden addr for cpp

* move code to a function

tests/arc/t19401.nim

@@ -0,0 +1,32 @@
+discard """
+  output: '''
+delete foo
+delete foo
+delete foo
+'''
+  matrix: "--mm:arc"
+"""
+
+type Foo = ref object
+  data: int
+proc delete(self: Foo) 
+proc newFoo: Foo =
+  let x = 12
+  discard x
+  new(result, delete)
+  result.data = x
+proc delete(self: Foo) =
+  doAssert self.data == 12
+  echo("delete foo")
+
+if isMainModule:
+  proc test() =
+    let x1 = newFoo()
+    let x2 = newFoo()
+    discard x1
+    discard x2
+    var x3: Foo
+    new(x3, delete)
+    x3.data = 12
+    discard x3
+  test()

tests/arc/t19402.nim

@@ -0,0 +1,32 @@
+discard """
+  output: '''
+delete foo
+delete foo
+delete foo
+'''
+  matrix: "--mm:arc"
+"""
+
+type Foo = ref object of RootObj
+  data: int
+proc delete(self: Foo)
+proc newFoo: Foo =
+  let x = 12
+  discard x
+  new(result, delete)
+  result.data = x
+proc delete(self: Foo) =
+  doAssert self.data == 12
+  echo("delete foo")
+
+if isMainModule:
+  proc test() =
+    let x1 = newFoo()
+    let x2 = newFoo()
+    discard x1
+    discard x2
+    var x3: Foo
+    new(x3, delete)
+    x3.data = 12
+    discard x3
+  test()