* Give descriptive error if auth method not found
Previously during a `consul login -method=blah`, if the auth method was not found, the
error returned would be "ACL not found". This is potentially confusing
because there may be many different ACLs involved in a login: the ACL of
the Consul client, perhaps the binding rule or the auth method.
Now the error will be "auth method blah not found", which is much easier
to debug.
Add a skip condition to all tests slower than 100ms.
This change was made using `gotestsum tool slowest` with data from the
last 3 CI runs of master.
See https://github.com/gotestyourself/gotestsum#finding-and-skipping-slow-tests
With this change:
```
$ time go test -count=1 -short ./agent
ok github.com/hashicorp/consul/agent 0.743s
real 0m4.791s
$ time go test -count=1 -short ./agent/consul
ok github.com/hashicorp/consul/agent/consul 4.229s
real 0m8.769s
```
Luke Kysow