message: Compile error fix for Apple clang version 12.0.0
  candidate function not viable: 'this'
  argument has type 'const TestMetadata', but method is not marked const
  bool operator<(const TestMetadata &o)
diff: @@ -242,7 +242,7 @@ struct TestMetadata
  bool IsAvailable() const { return test->Avail.empty(); }
  const char *AvailMessage() const { return test->Avail.c_str(); }
  - bool operator<(const TestMetadata &o)
  + bool operator<(const TestMetadata &o) const
  {
  if(API != o.API)
  return API < o.API;
  