Added translation for do statements with exit

final_lang/test2.fort

@@ -1,5 +1,6 @@
 program test
 integer :: a, b, c, d, x, y, z, w
+real :: e, f
 a = 2 + 4 * (2 + 1) / 3 * b
 b = a
 if (a > b) then 
@@ -11,4 +12,10 @@ elif (a > d) then
 else
     a = w
 end if
+do then
+    if (a > b .or. c > b) then
+        exit
+    end if
+    a = a + 1
+end do
 end program