How to reproduce:
1. Open the attached "SurvivalShooter" project
2. Perform a few Asset refreshes by pressing Ctrl + R (or CMD+R, if you are a Mac user) on the keyboard a few times
3. Observe Editor.Log and its Asset refresh times

Expected result: In 2017.2.0a2 and later, Asset refresh time should be around ~0.01 seconds, like in the 2017.2.0a1 and prior versions
Actual result: Asset refresh time is consistently around ~0.04 seconds in the 2017.2.0a2 and later versions

Regression introduced in - 2017.2.0a2
Reproducible with - 2017.3.0b3, 2017.2.0f2, 2017.2.0a2
Not reproducible with - 2017.2.0a1, 2017.1.1p4

Asset refresh time comparison between 2017.2.0a1 and 2017.2.0a2 versions in Survival Shooter project on Samsung SSD 850 EVO 250 GB, Windows 10 :
2017.2.0a1 -
Refresh: elapses 0.009462 seconds
Refresh: elapses 0.007476 seconds
Refresh: elapses 0.007297 seconds
Refresh: elapses 0.007508 seconds

2017.2.0a2 -
Refresh: elapses 0.040612 seconds
Refresh: elapses 0.060603 seconds
Refresh: elapses 0.039310 seconds
Refresh: elapses 0.039079 seconds