Simplify condition in Hash.[]

* The storage of an array is never null anymore.

Author: eregon

src/main/java/org/truffleruby/core/hash/HashNodes.java

@@ -94,8 +94,7 @@ protected Object construct(DynamicObject hashClass, Object[] args) {
                     final DynamicObject pairArray = (DynamicObject) pair;
                     final Object pairStore = Layouts.ARRAY.getStore(pairArray);
 
-                    if ((pairStore != null && pairStore.getClass() != Object[].class) ||
-                            (Layouts.ARRAY.getSize(pairArray) != 2)) {
+                    if (pairStore.getClass() != Object[].class || Layouts.ARRAY.getSize(pairArray) != 2) {
                         return fallbackNode.call(hashClass, "_constructor_fallback", args);
                     }