Both OpenGL and Metal are affected. The scene runs slower on the same target device.

Steps:
1. Build and Run Development build on iOS device ("Scripts.zip") with Unity 5.4
2. Connect Profiler > check BigTask.DoUpdate and SmallTask.DoUpdate
3. Do same with Unity 5.6 or older and compare results

Results:

version: BigTask.DoUpdate | SmallTask.DoUpdate (ms)

1) Standalone mac (seems to be not affected):
5.4.6f3: 2.2~3.0 | 14.6~15.2
5.6.3p5: 2.5~3.0 | 10.7~12.1
2017.2.0f2: 2.2~2.6 | 10.8~13.5
--
2) iPhone 5 iOS10.1.1 (openGL):
5.4.6f3: 13.6~14.5 | 0.05~0.1
5.6.3p5: 14.0~14.6 | 0.2~0.3
2017.2.0f2: 13.7~14.2 | 0.25~0.35
--
3)iPod 6th gen iOS10.2.1 (Metal):
5.4.6f3: 20.0~20.5 | 0.5
5.6.3p5: 24.0~25.0 | 0.5~0.8
2017.2.0f2: 24.7~25.2 | 0.5~0.8