RubyLB: Consume InlineItemResultRubyColumn::base_line

* Add PlaceRubyColumn().
* The `for` loop for InlineItemResults is moved to a new function, and
  PlaceRubyColumn() uses it.

This CL has no behavior changes due to a disabled runtime flag.

Bug: 324111880
Change-Id: I862d4186a6b23db8cc5e2556668bf0148758e822
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5382183


Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Auto-Submit: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1277269}