[starvation] improve deadlock reports

Summary:
The deadlock reports (the actual string) were too low level, in order to avoid bug hash clashes. Now that we deduplicate this is less of an issue, so it's an opportunity to improve readability.

```
      Potential deadlock.
    Trace 1 (starts at `void Interproc.interproc1Bad(InterprocA)`) first locks `this` in class `Interproc*` (line 9 in `void Interproc.interproc1Bad(InterprocA)`) and then locks `b` in class `InterprocA*` (line 14 in `void Interproc.interproc2Bad(InterprocA)`).
    Trace 2 (starts at `void InterprocA.interproc1Bad(Interproc)`), first locks `this` in class `InterprocA*` (line 37 in `void InterprocA.interproc1Bad(Interproc)`) and then locks `d` in class `Interproc*` (line 42 in `void InterprocA.interproc2Bad(Interproc)`).
```

Reviewed By: mbouaziz

Differential Revision: D8395399

fbshipit-source-id: b4bb48c

infer/src/concurrency/starvationDomain.ml

@@ -56,8 +56,6 @@ module type TraceElem = sig
 
   include PrettyPrintable.PrintableOrderedType with type t := t
 
-  val pp_no_trace : F.formatter -> t -> unit
-
   val make : elem_t -> Location.t -> t
 
   val get_loc : t -> Location.t
@@ -75,17 +73,7 @@ struct
   type t = {elem: Elem.t; loc: Location.t; trace: CallSite.t list [@compare.ignore]}
   [@@deriving compare]
 
-  let pp_no_trace fmt {elem; loc} = F.fprintf fmt "%a at %a" Elem.pp elem Location.pp loc
-
-  let pp fmt e =
-    let pp_trace fmt = function
-      | [] ->
-          ()
-      | trace ->
-          F.fprintf fmt " (trace: %a)" (Pp.semicolon_seq CallSite.pp) trace
-    in
-    F.fprintf fmt "%a%a" pp_no_trace e pp_trace e.trace
-
+  let pp fmt {elem; loc} = F.fprintf fmt "%a at %a" Elem.pp elem Location.pp loc
 
   let make elem loc = {elem; loc; trace= []}
 

infer/src/concurrency/starvationDomain.mli

@@ -27,8 +27,6 @@ module type TraceElem = sig
 
   include PrettyPrintable.PrintableOrderedType with type t := t
 
-  val pp_no_trace : F.formatter -> t -> unit
-
   val make : elem_t -> Location.t -> t
 
   val get_loc : t -> Location.t