How to reproduce:
1. Create a new project
2. Build it

Expected results: Build finishes in approx. 6-7 seconds, i.e. the build time on 2019.2.0b6
Actual results: Build finishes in twice the expected time (12-14 seconds)

Reproducible with: 2019.2.0b7, 2019.2.1f1, 2019.3.0a12
Not reproducible with: 2017.4.31f1, 2018.4.6f1, 2019.1.14f1, 2019.2.0b6

Additional notes:
1. The testing was done on a machine with i7-8700, GTX 1060 6GB, 16 GB RAM.
2. Removing Always Included Shaders in Player Settings -> Graphics didn't reduce the build time. These shaders are still being compiled.