JIT coverage can be improved considerably

[markshannon]

JIT coverage is still quite variable. For some benchmarks, e.g. richards it is close to 100%.
For others, much lower:

https://github.com/savannahostrowski/pyperf_bench/blob/main/profiling/jit.svg

Note: A fair bit of the time attributed to the interpreter is frame cleanup, so makes the interpreter fractions look larger than they are.

We can increase JIT coverage, by:

• Treating dynamic exits, like side exits: warming up and compiling a new, side, trace.
• Adding possible jit entry points at function entries, as well as backward edges.

[Fidget-Spinner]

For context, we increased JIT coverage by 50% just with trace recording alone. This was the old chart prior to trace recording https://github.com/faster-cpython/benchmarking-public/blob/main/profiling/jit.svg

[Fidget-Spinner]

@markshannon which one have you decided to work on? I can take up this issue if you aren't too far in yet, as I don't want to touch the JIT assembly parser in #143158 :).