Refactor: Simplify code to iterate on zip entries

A function called `for_each_file_entry` is introduced. It handles
iterating on zip entries and return with control flow. This reduces
boilerplate code and allows to better handle short-circuits with
`ControlFlow`.

Bug: 434562403
Change-Id: I3b566ba2d605d2fb51714aa66aa91d0a57d9ad1e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6786716
Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Łukasz Anforowicz <lukasza@chromium.org>
Reviewed-by: Łukasz Anforowicz <lukasza@chromium.org>
Auto-Submit: Michael Tatarski <mtatarski@google.com>
Cr-Commit-Position: refs/heads/main@{#1493737}