Rename PLACEHOLDER code kind to WASM_FUNCTION.

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1365613002

Cr-Commit-Position: refs/heads/master@{#30893}

src/log.cc

@@ -1645,8 +1645,8 @@ void Logger::LogCodeObject(Object* object) {
       description = "A keyed store IC from the snapshot";
       tag = Logger::KEYED_STORE_IC_TAG;
       break;
-    case Code::PLACEHOLDER:
-      description = "A placeholder for linking later code";
+    case Code::WASM_FUNCTION:
+      description = "A wasm function";
       tag = Logger::STUB_TAG;
       break;
     case Code::NUMBER_OF_KINDS:

src/objects.h

@@ -4621,7 +4621,7 @@ class Code: public HeapObject {
   V(HANDLER)                \
   V(BUILTIN)                \
   V(REGEXP)                 \
-  V(PLACEHOLDER)
+  V(WASM_FUNCTION)
 
 #define IC_KIND_LIST(V) \
   V(LOAD_IC)            \

src/snapshot/serialize.cc

@@ -2481,7 +2481,7 @@ void CodeSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
           SerializeGeneric(code_object, how_to_code, where_to_point);
         }
         return;
-      case Code::PLACEHOLDER:
+      case Code::WASM_FUNCTION:
         UNREACHABLE();
     }
     UNREACHABLE();