There are a couple of tests where the new code fails to produce a
prefix, but in those cases the prefixes are `""` and `{`, which are
not useful for filtering (and wrong for replacing). The new code does,
however, now find prefixes that the old code missed, which improves the
filtering. The changes to the tests reflect the improved filtering.
Change-Id: I3d48162ee56de1b94ecb3a88d11e8a2167fb8f2f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/372860
Reviewed-by: Keerti Parthasarathy <keertip@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>
Brian Wilkerson
e159bfee64