7156459: Remove unnecessary get() from Currency.getInstance()

Reviewed-by: chegar, dholmes, mduigou

src/share/classes/java/util/Currency.java

@@ -323,9 +323,10 @@ public final class Currency implements Serializable {
             }
         }
 
-        instance = instances.putIfAbsent(currencyCode,
-                   new Currency(currencyCode, defaultFractionDigits, numericCode));
-        return (instance != null ? instance : instances.get(currencyCode));
+        Currency currencyVal =
+            new Currency(currencyCode, defaultFractionDigits, numericCode);
+        instance = instances.putIfAbsent(currencyCode, currencyVal);
+        return (instance != null ? instance : currencyVal);
     }
 
     /**