Investigate intermittent crash in CacheOptimizeIndexBuffer on Editor startup on Linux

Building 4.10 from the GitHub release branch on Linux fails to open after install and instead crashes

Community Suggested Fix:
Switching triangle order optimization off with r.TriangleOrderOptimization=2 prevents the crash.

1. Clone github release branch to the computer
2. Run ./Setup.sh and ./GenerateProjectFiles.sh
3. Run "make ShaderCompileWorker UnrealLightmass UnrealPak UE4Editor
4. Navigate to Engine/Binaries/Linux folder
5. Run ./UE4Editor

Result:
Editor crashes during opening process.