Revert revision 39101 "Avoid linear search for function lookup."

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 39244)
+++ runtime/vm/object.h	(working copy)
@@ -949,7 +949,6 @@
   // Returns true if non-static fields are defined.
   bool HasInstanceFields() const;
 
-  // TODO(koda): Unite w/ hash table.
   RawArray* functions() const { return raw_ptr()->functions_; }
   void SetFunctions(const Array& value) const;
   void AddFunction(const Function& function) const;
@@ -1212,9 +1211,6 @@
 
   void CalculateFieldOffsets() const;
 
-  // functions_hash_table is in use iff there are at least this many functions.
-  static const intptr_t kFunctionLookupHashTreshold = 16;
-
   // Initial value for the cached number of type arguments.
   static const intptr_t kUnknownNumTypeArguments = -1;