[truffle] Stop passing an unneeded argument when declaring variables

Author: pmurias

src/vm/jvm/Truffle.nqp

@@ -1123,7 +1123,7 @@ class QAST::TruffleCompiler does SerializeOnce {
             elsif $node.decl eq 'var' || $node.decl eq 'static' {
                 my int $type := self.type_from_typeobj($node.returns);
                 $*BLOCK.register_var_type($node, $type);
-                @*DECLARATIONS.push(["declare-{$node.scope}", $type, $node.name, ["null"]]);
+                @*DECLARATIONS.push(["declare-{$node.scope}", $type, $node.name]);
             }
             elsif $node.decl eq 'param' {
                 $*BLOCK.add_param($node);

src/vm/jvm/runtime/org/perl6/nqp/truffle/ManageScopes.java

@@ -45,6 +45,7 @@
 import org.perl6.nqp.dsl.Deserializer;
 import org.perl6.nqp.truffle.nodes.NQPNode;
 import org.perl6.nqp.truffle.nodes.NQPBlockBodyNode;
+import org.perl6.nqp.truffle.nodes.expression.NQPNullNode;
 import org.perl6.nqp.truffle.nodes.control.NQPBlockNode;
 import org.perl6.nqp.truffle.nodes.control.NQPStaticBlockNode;
 import org.perl6.nqp.truffle.nodes.control.NQPForcedOuterBlockNode;
@@ -119,8 +120,8 @@ public static NQPScope declareLexical(NQPScope scope, long type, String name) {
     }
 
     @Deserializer("declare-lexical")
-    public static NQPNode createDeclareLexical(NQPScope scope, long type, String name, NQPNode inner) {
-        return inner;
+    public static NQPNode createDeclareLexical(NQPScope scope, long type, String name) {
+        return new NQPNullNode();
     }
 
     @Predeserializer("declare-local")
@@ -130,8 +131,8 @@ public static NQPScope declareLocal(NQPScope scope, long type, String name) {
     }
 
     @Deserializer("declare-local")
-    public static NQPNode createDeclareLocal(NQPScope scope, long type, String name, NQPNode inner) {
-        return inner;
+    public static NQPNode createDeclareLocal(NQPScope scope, long type, String name) {
+        return new NQPNullNode();
     }
 
     @Predeserializer("comp-unit")