[sledge] Build: Move Timer to Nonstdlib

Summary:
It has no dependencies on the rest of the sledge codebase and might be
more generally useful.

Reviewed By: jvillard

Differential Revision: D21720980

fbshipit-source-id: b4f061e73

infer/src/pulse/Pulse.ml

@@ -351,4 +351,4 @@ let checker ({InterproceduralAnalysis.proc_desc} as analysis_data) =
       None
 
 
-let () = Sledge.Timer.enabled := Config.sledge_timers
+let () = NS.Timer.enabled := Config.sledge_timers

sledge/nonstdlib/NS.ml

@@ -148,3 +148,5 @@ module Z = struct
 
   include Z
 end
+
+module Timer = Timer

sledge/nonstdlib/NS.mli

@@ -128,3 +128,5 @@ module Z : sig
   val is_true : t -> bool
   val is_false : t -> bool
 end
+
+module Timer = Timer

sledge/nonstdlib/timer.ml

@@ -7,6 +7,8 @@
 
 (** Timers for runtime statistics *)
 
+open NS0
+
 type t =
   { mutable ustart: float
   ; mutable sstart: float