Avoid an extra copy of a Ruby array for splat calls

* This partially reverts commit 7d45bc9.

Author: eregon

src/main/java/org/truffleruby/language/exceptions/RescueSplatNode.java

@@ -35,6 +35,7 @@ public RescueSplatNode(RubyLanguage language, RubyNode handlingClassesArray, Rub
                 SplatCastNode.NilBehavior.EMPTY_ARRAY,
                 false,
                 handlingClassesArray);
+        this.splatCastNode.doNotCopy();
         this.stores = ArrayStoreLibrary.getFactory().createDispatched(ArrayGuards.storageStrategyLimit());
     }
 

src/main/java/org/truffleruby/parser/BodyTranslator.java

@@ -700,6 +700,14 @@ protected ArgumentsAndBlockTranslation translateArgumentsAndBlock(SourceIndexLen
             argumentsTranslated[i] = arguments[i].accept(this);
         }
 
+        if (isSplatted) {
+            assert argumentsTranslated.length == 1;
+            // No need to copy the array for call(*splat), the elements will be copied to the frame arguments
+            if (argumentsTranslated[0] instanceof SplatCastNode) {
+                ((SplatCastNode) argumentsTranslated[0]).doNotCopy();
+            }
+        }
+
         ParseNode blockPassNode = null;
         if (iterNode instanceof BlockPassParseNode) {
             blockPassNode = ((BlockPassParseNode) iterNode).getBodyNode();