allow autofree in with var NAME : TYPE := EXPR do

Form D's `:= EXPR` branch now accepts the `autofree` keyword the same
way Form C does. The class-instance check downstream rejects autofree
on non-class targets, so aggregate-literal init (records/arrays) still
errors as expected. Brings Form D to full feature parity with Form C
on the autofree axis.

```pas
with var a: TStringList := autofree TStringList.Create do
  a.Add('hello');
// a.Free called here
```

Author: fibodevy

compiler/pstatmnt.pas

@@ -1697,12 +1697,19 @@       twithshadowcand = class
                      lifetime_init := nil;
                      if try_to_consume(_ASSIGNMENT) then
                        begin
+                         if current_scanner.token = _AUTOFREE then
+                           begin
+                             consume(_AUTOFREE);
+                             lifetime_autofree := true;
+                             lifetime_init := comp_expr([ef_accept_equal]);
+                             do_typecheckpass(lifetime_init);
+                           end
                          { Aggregate literal init for record/array: reuse
                            typed-constant parser via a hidden static sym,
                            then copy it into the with-var. The plain
                            expression parser cannot handle (a, b, c) form. }
-                         if (current_scanner.token = _LKLAMMER) and
-                            ((hdef.typ = arraydef) or (hdef.typ = recorddef)) then
+                         else if (current_scanner.token = _LKLAMMER) and
+                                 ((hdef.typ = arraydef) or (hdef.typ = recorddef)) then
                            begin
                              lifetime_tcsym := cstaticvarsym.create(
                                '$with_tc_' + lifetime_name, vs_const, hdef, []);