delphi mode: pointer add operator symetry
Delphi supports simetry on pointer + operator. It can both:
`y := ptr + c;
y = c + ptr;`
But FPC fails on second.
On delphi 7 code below compile well:
```
unit test_ptr_distrib;
{$IFDEF FPC}
{$MODE Delphi}
{$ENDIF}
interface
uses sysutils;
function ptr_twist() : boolean;
implementation
function ptr_twist() : boolean;
var
x : pchar;
x2 : pchar;
const
str : ShortString = '123456789';
begin
x := @(str[2]);
x := x + 5;
x2:= 5 + x; // FPC fails here
result := (x = x2);
end;
end.
```
imho, pointer sum simmetry gives less troubles on delphi code import
issue