Rename dangling-markup-window-name test

Since the dangling markup in target name is merged to the html spec[1],
let's remove the tentative name from the test.

[1] whatwg/html#9309

Bug: 1421440
Change-Id: I75a47e0c155cd81f72eafe45a9118a93b8904ba7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4827645
Auto-Submit: Jun Kokatsu <jkokatsu@google.com>
Reviewed-by: Yifan Luo <lyf@chromium.org>
Commit-Queue: Yifan Luo <lyf@chromium.org>
Commit-Queue: Jun Kokatsu <jkokatsu@google.com>
Cr-Commit-Position: refs/heads/main@{#1190256}