FullCodegen generates 2 statement positions for the loop init block, like so:

  for(var i = 0; i....
      ^   ^

This change removes the first of those, updates unit tests,
and removes text expectations for Ignition.

---
An alternative would be to emulate the existing behaviour in Ignition, but:
- The new behaviour seems more logical,
- Ignition generates no bytecodes for the 'var', meaning there is no code position to attach the break position to.

BUG=v8:4690
LOG=Y

Review URL: https://codereview.chromium.org/1784883002

Cr-Commit-Position: refs/heads/master@{#34717}