Optimize push 2

[hackaugusto]

Describe your changes

This encodes the same value a little bit more effectively:

• The instruction Push.2 takes one Op and a group (about 71bits).
• The instructions Padd Incr Incr take 3 Ops (about 21 bits).

Checklist before requesting a review

• Repo forked and branch created from next according to naming convention.
• Commit messages and codestyle follow conventions.
• Relevant issues are linked in the PR description.
• Tests added for new functionality.
• Documentation/comments updated according to changes.

[hackaugusto]

There are some CI errors, seems the tests are checking the clock count. I will fix this if the PR gets a go ahead.

[hackaugusto]

but also not sure if it is worth the effort as we'd also need to update cycle counts for downstream operations which use append_pow2_op

closing this