Reproduction Steps:
1. Open attached project "873528 - TimeClassBug".
2. Go to "Test" -> "Time Bug" in the menu.
3. Observe how the Time values are not 0 before entering Play mode.
4. Move around the "Time Bug" tab in Unity Editor.
5. Notice how Time values continue to change. (GIF attached)

Expected result: Time values (besides frameCount) should be 0 before entering Play mode.
Actual result: Time values give out unknown values before entering Play mode.

Reproducible on: 5.6.0b5, 5.5.1f1
Not reproducible on: 5.4.3p3, 5.3.7p2, 5.2.5f1
Regression introduced in: 5.5.0f3