[RemoveLegacy] Remove LayoutTextControl* and TextControlSingleLinePainter

* Change LayoutTextControl class to layout_text_control namespace
https://google.github.io/styleguide/cppguide.html#Nonmember,_Static_Member,_and_Global_Functions
> Do not use a class simply to group static members.

* Rename IsTextAreaIncludingNG() to IsTextArea()
* Rename IsTextControlIncludingNG() to IsTextControl()
* Rename IsTextFieldIncludingNG() to IsTextField()

This CL has no behavior changes.

Bug: 1229581
Change-Id: Id44c70d7c4aa97f2bc106743ddacb157158f341e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4374219
Auto-Submit: Kent Tamura <tkent@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1122854}