[patternmatch] fix wrong regexp in getter detection

Summary: The regexp would match `ge` and is also unnecessary and was compiled on every call. Save some cpu cycles while fixing it.

Reviewed By: jvillard

Differential Revision: D17789586

fbshipit-source-id: a3f6612c6

infer/src/absint/PatternMatch.ml

@@ -233,9 +233,7 @@ let get_vararg_type_names tenv (call_node : Procdesc.Node.t) (ivar : Pvar.t) : s
   type_names [] call_node
 
 
-let is_getter pname_java =
-  Str.string_match (Str.regexp "get*") (Typ.Procname.Java.get_method pname_java) 0
-
+let is_getter pname_java = String.is_prefix ~prefix:"get" (Typ.Procname.Java.get_method pname_java)
 
 let type_is_class typ =
   match typ.Typ.desc with