message: [lldb] [unittests] Use non-empty format string for Timer()
  Pass dummy '.' as format string for Timer() rather than an empty string,
  in order to silence gcc warnings about empty format string
  (-Wformat-zero-length).  The actual format string is irrelevant
  to the test in question.
diff: @@ -17,7 +17,7 @@ TEST(TimerTest, CategoryTimes) {
  Timer::ResetCategoryTimes();
  {
  static Timer::Category tcat("CAT1");
  - Timer t(tcat, "");
  + Timer t(tcat, ".");
  std::this_thread::sleep_for(std::chrono::milliseconds(10));
  }
  StreamString ss;
  @@ -32,10 +32,10 @@ TEST(TimerTest, CategoryTimesNested) {
  Timer::ResetCategoryTimes();
  {
  static Timer::Category tcat1("CAT1");
  - Timer t1(tcat1, "");
  + Timer t1(tcat1, ".");
  std::this_thread::sleep_for(std::chrono::milliseconds(10));
  // Explicitly testing the same category as above.
  - Timer t2(tcat1, "");
  + Timer t2(tcat1, ".");
  std::this_thread::sleep_for(std::chrono::milliseconds(10));
  }
  StreamString ss;
  @@ -52,10 +52,10 @@ TEST(TimerTest, CategoryTimes2) {
  Timer::ResetCategoryTimes();
  {
  static Timer::Category tcat1("CAT1");
  - Timer t1(tcat1, "");
  + Timer t1(tcat1, ".");
  std::this_thread::sleep_for(std::chrono::milliseconds(100));
  static Timer::Category tcat2("CAT2");
  - Timer t2(tcat2, "");
  + Timer t2(tcat2, ".");
  std::this_thread::sleep_for(std::chrono::milliseconds(10));
  }
  StreamString ss;
  