Message 270505 - Python tracker

Nice idea, Antti. But I tried to implement it, and surprisingly found that this approach is slower than FORMAT_VALUE + BUILD_STRING. At least for this particular example. Perhaps because we can't use a stack and need to allocate a new tuple containing literal strings and formatted values for PyUnicode_Join(). Not mentioning that the code is much more complex.

Here is updated previous patch with fixed leak.