Remove local autofocus tests in favor of WPT

https://bugs.webkit.org/show_bug.cgi?id=279590
rdar://135867353

Reviewed by Antoine Quint.

This patch removes local tests which were uploaded to WPT by Blink / Chromium,
in following commits [1] & [2]:

[1] web-platform-tests/wpt#22133
[2] https://chromium-review.googlesource.com/c/chromium/src/+/2094058

The test replacing below is named `no-autofocus-on-changing-input-type.html`,
it is present in our tree and passes on all platforms.

* LayoutTests/fast/forms/autofocus-focus-only-once-expected.txt: Removed.
* LayoutTests/fast/forms/autofocus-focus-only-once.html: Removed.
* LayoutTests/fast/forms/autofocus-opera-001-expected.txt: Removed.
* LayoutTests/fast/forms/autofocus-opera-001.html: Removed.
* LayoutTests/fast/forms/autofocus-opera-006-expected.txt: Removed.
* LayoutTests/fast/forms/autofocus-opera-006.html: Removed.
* LayoutTests/fast/forms/autofocus-opera-008-expected.txt: Removed.
* LayoutTests/fast/forms/autofocus-opera-008.html: Removed.

Canonical link: https://commits.webkit.org/283556@main