LibJS: Fix null deref in ObjectProperty::dump()

Author: https://github.com/davidot
Commit: 1fe6a422f1
Pull-request: https://github.com/SerenityOS/serenity/pull/10483
Issue: https://github.com/SerenityOS/serenity/issues/8198
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibJS/AST.cpp

@@ -2272,8 +2272,15 @@ void VariableDeclarator::dump(int indent) const
 void ObjectProperty::dump(int indent) const
 {
     ASTNode::dump(indent);
-    m_key->dump(indent + 1);
+
-    m_value->dump(indent + 1);
+    if (m_property_type == Type::Spread) {
+        print_indent(indent + 1);
+        outln("...Spreading");
+        m_key->dump(indent + 1);
+    } else {
+        m_key->dump(indent + 1);
+        m_value->dump(indent + 1);
+    }
 }
 
 void ObjectExpression::dump(int indent) const