Fix dissassembler and AVM2 shell.
Perform a dirty local analysis to prevent the insertion of unnecessary PHI nodes.

This should speed things up quite a bit, at least in terms of compilation time.
Take care of hasNext2 since it touches locals.
Cleaning up.
More cleanup.
Don't self host push and pop.

This can get us huge boosts in speed and we should do this for all natives. Startup time will also improve if we go through all of these and route them to JS versions.