Steps to reproduce:
1. Open the attached project ("1195759.zip")
2. Select the "Minecrafy.fbx" file in the Project window
3. Click on any of the clips in the Inspector window of the fbx (open the Animation tab if not yet opened)

Expected result: Unity is not noticeably slower than before
Actual result: Unity lag spikes whenever the Clip Inspector in the Animation tab is interacted with

Reproducible with: 2019.2.0a6, 2019.2.14f1, 2019.3.0f1, 2020.1.0a15
Not reproducible with: 2017.4.35f1, 2018.4.13f1, 2019.2.0a5

Notes:
- In versions that I classified as not reproducible, same process would take up 20-40 Time ms and 10-35 Self ms while in the versions I deemed reproducible it took 350-700 Time ms and 350-700 Self ms
- Results were measured with 250 default clips of the fbx in the project