[decompiler] fix missing casts issue (#573)

* fix casts issue

* fix bug

* one last small fix

test/decompiler/reference/engine/ui/hud-h_REF.gc

@@ -183,9 +183,5 @@
   )
 
 ;; failed to figure out what this is:
-(let ((v0-4 0))
+(let ((v0-8 0))
   )
-
-
-
-

test/decompiler/reference/engine/ui/text-h_REF.gc

@@ -65,5 +65,5 @@
 (define *common-text* (the-as game-text-info #f))
 
 ;; failed to figure out what this is:
-(let ((v0-3 0))
+(let ((v0-5 0))
   )