[send-sync-blocks-async.htm]
  [XMLHttpRequest: sync requests should block events on pending async requests]
    expected:
      if not debug and (os == "linux") and not asan and not tsan: [FAIL, PASS]
      if not debug and (os == "win"): [FAIL, PASS]
      if not debug and (os == "mac"): [PASS, FAIL]
      if not debug and (os == "android"): [FAIL, PASS]