message: Fix Syntax errors on IE11 tests.
diff: @@ -1752,13 +1752,15 @@ skipOnBrowser("debugging and messages and optimizations", () => {
  })
  it("not report unicode flag", () => {
  - const One = createToken({ name: "One", pattern: /1/u })
  + // using new RegExp() to avoid IE 11 syntax errors
  + const One = createToken({ name: "One", pattern: new RegExp("1", "u") })
  new Lexer([One], { positionTracking: "onlyOffset" })
  expect(console.error).to.have.not.been.called
  })
  it("report unicode flag with ensureOptimizations enabled", () => {
  - const One = createToken({ name: "One", pattern: /1/u })
  + // using new RegExp() to avoid IE 11 syntax errors
  + const One = createToken({ name: "One", pattern: new RegExp("1", "u") })
  expect(
  () =>
  new Lexer([One], {
  @@ -1793,7 +1795,8 @@ skipOnBrowser("debugging and messages and optimizations", () => {
  })
  it("Will report mutually exclusive safeMode and ensureOptimizations flags", () => {
  - const One = createToken({ name: "One", pattern: /1/u })
  + // using new RegExp() to avoid IE 11 syntax errors
  + const One = createToken({ name: "One", pattern: new RegExp("1", "u") })
  expect(
  () =>
  new Lexer([One], {
  