Reproduction steps:
1. Open user's attached project
2. In Profiler window, set profiling to Editor mode
3. Open /Assets/Scripts/AI/OfficeWorkerAI.cs using notepad
4. In "Awake()" function, add a space to the Debug.LogWarning string and save script
5. In Profiler window, observe performance

Expected result: Asset reimport is fast
Actual result: Asset reimport is considerably slow

Reproducible with: 2019.4.9f1, 2020.1.4f1, 2020.2.0b1
Could not test with: 2018.4.27f1 (console errors break project)

Note: Issue reproduces using Asset Import Pipeline V1 and V2
Note 2: The repro project here has been found to have very slow reload time due to Console Pro. If you have a lot of assert,warning the domain reload is greatly impacted negatively due to the usage of Console Pro. To improve you can enable "Collapse" mode which helps or close the Console Pro window. In this case, going from non-collapse Console Pro mode ~25 seconds to ~2.5 seconds in collapse mode and less without Console Pro.
Note 3: Investigating a duplicate issue it was observed that having the Package Manager window open will result in degradation of domain reload time over the course of a session. This is being fixed and tracked here: https://issuetracker.unity3d.com/issues/compilation-and-refresh-time-increases-after-each-script-change
Note 4: If you use Burst, upgrading to Burst 1.4.0-preview.5 should allow to save some time. In the case of this project it will save 0.2 seconds on every domain reload.
Note 5: If your domain reload times are not caused by one of the above issue, please report a separate issue with your project so that we can investigate. Thank you!