[turbofan] Factor out the function specific part from the frame state operator.

src/compiler/instruction.cc

Index: src/compiler/instruction.cc
diff --git a/src/compiler/instruction.cc b/src/compiler/instruction.cc
index 815e91e930bc406dcd55c25c854a2a093dd50464..83b45b39ddec69baaac0d80e37c58654c5b49933 100644
--- a/src/compiler/instruction.cc
+++ b/src/compiler/instruction.cc
@@ -721,7 +721,7 @@ size_t FrameStateDescriptor::GetJSFrameCount() const {
   size_t count = 0;
   for (const FrameStateDescriptor* iter = this; iter != NULL;
        iter = iter->outer_state_) {
-    if (iter->type_ == JS_FRAME) {
+    if (iter->type_ == FrameStateType::kJavaScriptFunction) {
       ++count;
     }
   }