Message 137788 - Python tracker

Updated the title to reflect that the peephole optimizer will likely continue to exist but in a much simpler form.  Some complex peephole optimization such as constant folding can be handled more easily and more robustly at the AST level.

Other minor peephole optimizations such as jump-to-jump simplification as still bytecode level optimizations (ones that improve the quality of the generated code without visibility to higher level semantics).