Fix expectations for a few more tests for DefaultSiteInstanceGroups

This CL is relanding just the test expectation updates from
https://chromium-review.googlesource.com/c/chromium/src/+/6625492.

It updates expectations for a few remaining tests to work properly
with default SiteInstanceGroups. These are mostly about no longer
checking for default SiteInstance (or its unisolated.invalid site URL)
when default SiteInstanceGroups are enabled, since they produce
SiteInstances with meaningful site URLs. This is most easily
accomplished by using AreStrictSiteInstancesEnabled() to account for
both strict site isolation and default SiteInstanceGroups.  All these
updates are test expectation changes rather than product behavior
updates, apart from the slight difference in how one metric is
reported for COOP process reuse (see PS3..PS4 diffs).

Bug: 390571607
Change-Id: I07d6eb1582d952c2479d8c15c7c8543fb050efc2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6626983
Commit-Queue: Lei Zhang <thestig@chromium.org>
Auto-Submit: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: Charlie Reis <creis@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1470626}