[runtime] Introduce dedicated JSBoundFunction to represent bound functions.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 052e09483229f60f25bb714da7f5411a8a07715b..6e8ce129597902a2c0971567d316b995a9a7de6b 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -815,11 +815,8 @@ static void InsertCodeIntoOptimizedCodeMap(CompilationInfo* info) {
   // Frame specialization implies function context specialization.
   DCHECK(!info->is_frame_specializing());
 
-  // Do not cache bound functions.
-  Handle<JSFunction> function = info->closure();
-  if (function->shared()->bound()) return;
-
   // Cache optimized context-specific code.
+  Handle<JSFunction> function = info->closure();
   Handle<SharedFunctionInfo> shared(function->shared());
   Handle<LiteralsArray> literals(function->literals());
   Handle<Context> native_context(function->context()->native_context());