fix tools/domprops.json is not mixed in reserved, when use API option Mangle properties

lib/propmangle.js

@@ -62,6 +62,7 @@ function find_builtins(reserved) {
             Object.getOwnPropertyNames(ctor.prototype).map(add);
         }
     });
+    domprops.forEach(add);
     function add(name) {
         push_uniq(reserved, name);
     }

tools/node.js

@@ -23,6 +23,7 @@ new Function("MOZ_SourceMap", "exports", function() {
         return fs.readFileSync(file, "utf8");
     });
     code.push("exports.describe_ast = " + describe_ast.toString());
+    code.push(";var domprops = " + JSON.stringify(require("./domprops.json")));
     return code.join("\n\n");
 }())(
     require("source-map"),