PMM-12468 Plan summary, COLLSCAN.

[JiriCtvrtka]

Ticket on PMM side: https://perconadev.atlassian.net/browse/PMM-12468

• The contributed code is licensed under GPL v2.0
• Contributor Licence Agreement (CLA) is signed
• util/update-modules has been ran
• Documentation updated
• Test suite update

[it-percona-cla]

All committers have signed the CLA.

[svetasmirnova]

Please add regression tests.

[BupycHuk]

@svetasmirnova where can we find CI tests execution results?

[svetasmirnova]

@BupycHuk

I expect you to add tests to src/go/mongolib/proto/system.profile_test.go and src/go/mongolib/stats/stats_test.go and run those tests locally when change code.

Proper testing for Go tools is planned but not done yet.

[JiriCtvrtka]

@svetasmirnova

The stats_test.go tests are currently completely skipped (even locally).
Check skip here
I re-enabled them in this PR, but they are failing even without any changes. So they have probably been broken for a while.

The system.profile_test.go tests, which check explain and my changes about plan summary, are not related to it.

Due to the issues mentioned above, I created a ticket:
PMM-13736
to address these problems (failing tests and possible incorrect BSON tags in system.profile lock properties).

Additionally, I corrected some other tests, such as:
Check example of corrected cleanup,
where the previous code could cause incorrect cleanup after tests (direct exit will ignore defer functions).

Would you agree to merge this PR and cover my changes with tests in the ticket, where we will fix the stats tests and related issues together?

[svetasmirnova]

OK, approving it now. Let's fix tests in https://perconadev.atlassian.net/browse/PT-2423