This will require a change to the internal line number table format.

PEP 626 requires all lines are traced, which makes handling of 'continue' and other jump-to-jumps inefficient if spread across multiple lines.

In 3.9 many jump-to-jumps were eliminated, but PEP 626 requires that many are converted to a NOP. Zero-width line number table entries will allow us to eliminate most, if not all, remaining NOPs in the assembler.