[WPT] [CSP] Increase timeout of history-iframe test
On Win11 arm the test takes ~6s when it succeeds, and it times out at
7s. Let's try to increase the timeout.
Bug: 349414735
Change-Id: Ide690f5b0094c1700b87d1fc7d83d4872b43039e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5724749
Reviewed-by: Jonathan Hao phao@chromium.org
Commit-Queue: Antonio Sartori antoniosartori@chromium.org
Cr-Commit-Position: refs/heads/main@{#1331000}