[FedCM] Fix fedcm-iframe.https.html with wptrunner
- Only wait for the expected message
- Add a required call to set_test_context in two iframes
Bug: 331237776
Change-Id: I5d4b14031288573715a0630aa94a4ebcb8e0ed04
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5754107
Reviewed-by: Nicolás Peña npm@chromium.org
Auto-Submit: Christian Biesinger cbiesinger@chromium.org
Commit-Queue: Christian Biesinger cbiesinger@chromium.org
Cr-Commit-Position: refs/heads/main@{#1335689}