Rename CurrentMapForDeprecated to TryUpdate, and introduce Map::Update which potentially deprecates

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index 84d828ebb9d40ac7505dfe16b8b8e99332e1b644..245ea1189274c33560c174a21db3dac309c7a2d9 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -265,7 +265,7 @@ class SmallMapList V8_FINAL {
   int length() const { return list_.length(); }
 
   void AddMapIfMissing(Handle<Map> map, Zone* zone) {
-    if (!Map::CurrentMapForDeprecated(map).ToHandle(&map)) return;
+    if (!Map::TryUpdate(map).ToHandle(&map)) return;
     for (int i = 0; i < length(); ++i) {
       if (at(i).is_identical_to(map)) return;
     }