* Refactor integration tests to use annotations functions
First part of #4176
Replaced all the `t.Error`/`t.Fatal` calls in the integration with the
new functions defined in `testutil/annotations.go` as described in #4292,
in order for the errors to produce Github annotations.
Most of these calls have now two strings: one containing a generic error
message and another with a more specific message. The former is what
will be aggregated and seen in the CI reports at
[linkerd2-ci-metrics](https://github.com/linkerd/linkerd2-ci-metrics).
Other changes:
- Improved the annotation generator in `annotations.go` so that the
message includes the name of the test.
- When a failure from `RetryFor` occurs, log the original timeout so
we can consider incrementing it when the failure is persistent.
In various integration tests we're not showing stderr when a failure
happens, thus hiding some possibly useful debugging info.
E.g. in the latest CI failures, commands like `linkerd update` were
failing with no visible reason why.
Alejandro Pedraza
Zahari Dichev
Dennis Adjei-Baah
Andrew Seigner