8252990: Intrinsify Unsafe.storeStoreFence

Reviewed-by: dholmes, thartmann, whuang

src/java.base/share/classes/jdk/internal/misc/Unsafe.java

@@ -3441,16 +3441,14 @@ public final class Unsafe {
      * Ensures that stores before the fence will not be reordered with
      * stores after the fence.
      *
-     * @implNote
-     * This method is operationally equivalent to {@link #storeFence()}.
-     *
      * @since 9
      */
+    @IntrinsicCandidate
     public final void storeStoreFence() {
+        // If storeStoreFence intrinsic is not available, fall back to storeFence.
         storeFence();
     }
 
-
     /**
      * Throws IllegalAccessError; for use by the VM for access control
      * error support.