[nnbd_migration] Fix #41795, delete/change hint causes rerun.

This is only an issue for the old style (not in stacktrace) buttons.

I did not add a test for this; there are many tests for this code in the
new workflow, inside UnitInfo.handleSourceEdit, etc, and this code path
will be removed soon hopefully.

I *did* test manually and saw that it works.

Change-Id: Iac8ba4cb775b9b15c8db1c1cadd4701da81452be
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149382
Commit-Queue: Paul Berry <paulberry@google.com>
Auto-Submit: Mike Fairhurst <mfairhurst@google.com>
Reviewed-by: Paul Berry <paulberry@google.com>

https://dart.googlesource.com/sdk/+/42b71b8f9e1dd8730e89321e760cd0579afc5125
1 file changed
tree: ccf8f43c3bd7b054689314559d16249e8792d761
  1. commits.json