Cheaper thread-safe atomic initialization of static references.

Source/wtf/unicode/icu/CollatorICU.cpp

Index: Source/wtf/unicode/icu/CollatorICU.cpp
diff --git a/Source/wtf/unicode/icu/CollatorICU.cpp b/Source/wtf/unicode/icu/CollatorICU.cpp
index a21e9325a5add6c86844373e4bb8b07ca1e06ffb..93e95a1bd83793c075ae79e98a47b2e06c7dc395 100644
--- a/Source/wtf/unicode/icu/CollatorICU.cpp
+++ b/Source/wtf/unicode/icu/CollatorICU.cpp
@@ -47,7 +47,7 @@ namespace WTF {
 static UCollator* cachedCollator;
 static Mutex& cachedCollatorMutex()
 {
-    AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex);
+    AtomicallyInitializedStaticReference(Mutex, mutex, new Mutex);
     return mutex;
 }