Fix wpt test failures on tests with non-ascii search params
The browser was not treating the html as UTF-8 so there was a problem
with the encoding of the prefetch and navigation params.
Specifying utf-8 encoding fixes the failures.
Bug: 340928303, 343754418
Change-Id: Icab8eca128cf94b9c33b18453798b4f6e87b4e06
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5957709
Commit-Queue: Liviu Tinta liviutinta@chromium.org
Reviewed-by: Hiroki Nakagawa nhiroki@chromium.org
Cr-Commit-Position: refs/heads/main@{#1373293}