add missing copyright header

Author: matthewbastien

test/unit-tests/commands/runTestMultipleTimes.test.ts

@@ -1,3 +1,17 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2025 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of VS Code Swift project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
 import * as vscode from "vscode";
 import { expect } from "chai";
 import { extractTestItemsAndCount } from "../../../src/commands/testMultipleTimes";