How to reproduce:
1. Open the attached project
2. Open the "SampleScene" from the Scene folder
3. Inspect that the Scene view has no shadows
4. Go to Menu bar-> Edit-> Project Settings-> Quality-> Levels
5. Delete Very low and Low levels
6. Inspect the Scene view and see that the shadows now are rendered (see the video in the comments)

Actual: Shadows aren't rendered with "Low" and "Very Low" Quality levels

Reproducible with: 2018.3.14f1, 2018.4.2f1, 2019.1.0b9

Not Reproducible with: 2019.1.0b10, 2019.1.7f, 2019.2.0b6, 2019.3.0a6

Note: The issue is fixed but backport is needed, check the comments for the link to the possible fix