[sledge] Don't call Llvm.dispose_context as it leads to crashes in GC

Summary:
The root cause is not clear, but it seems that not calling
Llvm.dispose_context avoids segfaults in the GC.

Reviewed By: kren1

Differential Revision: D15535434

fbshipit-source-id: 280e44d0b

sledge/src/llair/frontend.ml

@@ -1391,7 +1391,6 @@ let translate : string -> Llair.t =
   Hashtbl.clear memo_value ;
   Hash_set.clear ignored_callees ;
   Llvm.dispose_module llmodule ;
-  Llvm.dispose_context llcontext ;
   Llair.mk ~globals ~functions
   |>
   [%Trace.retn fun {pf} _ -> pf ""]