[flow][easy] rename mk_exact_empty to mk_frozen_exact_empty

Summary:
This function enables the "frozen" flag that cannot be used lightly, since it makes the assumption that the object it refers to is unaliased. This diff updates its name to make this more clear.

Changelog: [internal]

Reviewed By: SamChou19815

Differential Revision: D57134537

fbshipit-source-id: 49d81e02b853f7aac4b79508abf05aef36eb48be

src/typing/obj_type.ml

@@ -36,7 +36,7 @@ let mk_with_proto
   in
   DefT (reason, ObjT (mk_objecttype ?reachable_targs ~flags ~call pmap proto))
 
-let mk_exact_empty cx reason =
+let mk_frozen_exact_empty cx reason =
   ObjProtoT reason |> mk_with_proto cx reason ~obj_kind:Exact ~frozen:true
 
 let mk ~obj_kind cx reason = mk_with_proto cx ~obj_kind reason (ObjProtoT reason)

src/typing/statement.ml

@@ -2208,7 +2208,7 @@ module Make
         in
         Flow.flow cx (elem_t, check);
         (* No properties are added in this case. *)
-        Obj_type.mk_exact_empty cx reason_obj
+        Obj_type.mk_frozen_exact_empty cx reason_obj
       | Named { name; reason; _ } ->
         let prop =
           Field

src/typing/type_sig_merge.ml

@@ -430,7 +430,7 @@ let merge_exports =
       let exports =
         match exports with
         | Some (lazy t) -> t
-        | None -> Obj_type.mk_exact_empty file.cx reason
+        | None -> Obj_type.mk_frozen_exact_empty file.cx reason
       in
       let type_exports = SMap.map Lazy.force type_exports |> NameUtils.namemap_of_smap in
       let type_stars = List.map (merge_star file) type_stars in
@@ -1879,7 +1879,7 @@ and merge_component
     let param =
       let rest_t =
         match rest_param with
-        | None -> Obj_type.mk_exact_empty file.cx config_reason
+        | None -> Obj_type.mk_frozen_exact_empty file.cx config_reason
         | Some (Type_sig.ComponentRestParam { t }) -> merge env file t
       in
       EvalT