PaymentHandler: Fix change-payment-method.https.html test

Before this patch, TypeError occurs due to the wrong order of test
scripts. The error causes test failure and shutting down but service
worker registration might be going on different thread. At that time,
the service worker might not register to a finish and might cause DB
errors internally. It might eventually cause a crash due to DCHECK.
So, this patch fixes the wrong order of test scripts. After this patch,
TypeError no longer occurs and we guarantee that service worker is
activated at least.

Bug: 964158
Change-Id: Id8ebe86de3c558e81aad732c6ef6b513647f6465
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1619531
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Commit-Queue: Rouslan Solomakhin <rouslan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661388}
2 files changed