Test fixes

[forsyth2]

Summary

Objectives:

• Make legacy 3.1.0 references consistent with 3.0.0
• Always run land_monthly subtask, as it's needed by e3sm_diags AND ilamb

Issue resolution:

• Resolves issues noted here (incorrect legacy 3.1.0 setup) & here (incorrect activation command for land_monthly)

Select one: This pull request is...

• a bug fix: increment the patch version
• a small improvement: increment the minor version
• a new feature: increment the minor version
• an incompatible (non-backwards compatible) API change: increment the major version

Small Change

• To merge, I will use "Squash and merge". That is, this change should be a single commit.
• Logic: I have visually inspected the entire pull request myself.
• Pre-commit checks: All the pre-commits checks have passed.

[forsyth2]

Another fix to add: don't delete test_campaign output directories at the end of each test. That's causing issues with updating the expected results.
E.g.,:

# assert os.system("rm -r test_campaign_water_cycle_override_output") == 0

EDIT: test_defaults.py could also use this fix.

[forsyth2]

Commit 2 needed while testing #774.

[forsyth2]

I removed Commit 2 since it was determined to be unnecessary. In #774 (comment):

I had extended the time limit here because it was hitting the time limit, but it turns out the time limit isn't the problem at all. The job stays active even after the segmentation fault, but doesn't actually do anything to recover from it.

[forsyth2]

I think this is ready to merge. I've tested the primary (and now only) commit while testing multiple other PRs. Furthermore, #772 will be incorporating changes to the v3 test cfg, so we should now enable the 3.1.0 legacy test cfgs (which this commit does). That is, the primary test cfg will soon diverge from the 3.1.0 legacy test cfg, so it will actually be important to test both.