Blender Git Loki

Revert "Cycles: Change OpenCL split kernel to use single program by default"

This reverts commit c6bf5d47240cebef356276e369881e855dbe7e6d.

Related to D2264: When multi process opencl kernel compilation is in place single-program compiles slower then multi-program. c6bf5d47240cebef356276e369881e855dbe7e6d was created as single-program compiled faster, but this is not the case anymore. So let's revert this change. Production scenes like victor and barbershop even render quicker.

Change in Cycles OpenCL compilation times

> job | scene_name | compilation_time | render_time
> Baseline | empty | 22.73 | 20.63
> T61514 | empty | 10.63 | 21.06
> Baseline | bmw | 56.44 | 191.00
> T61514 | bmw | 17.91 | 198.44
> Baseline | fishycat | 59.50 | 393.48
> T61514 | fishycat | 19.57 | 394.20
> Baseline | barbershop | 212.28 | 1623.53
> T61514 | barbershop | 54.10 | 1188.16
> Baseline | victor | 67.51 | 1459.80
> T61514 | victor | 22.06 | 1381.58
> Baseline | classroom | 51.46 | 341.23
> T61514 | classroom | 17.55 | 341.08
> Baseline | koro | 62.48 | 475.96
> T61514 | koro | 18.92 | 472.43
> Baseline | pavillion | 54.37 | 903.48
> T61514 | pavillion | 17.43 | 905.77
> Baseline | splash279 | 47.43 | 52.92
> T61514 | splash279 | 16.48 | 55.26
> Baseline | volume_emission | 145.22 | 62.38
> T61514 | volume_emission | 36.22 | 62.59

Reviewers: #cycles, brecht, sergey

Reviewed By: #cycles, brecht

Differential Revision: https://developer.blender.org/D4349