Fix #34889: negative lights not working in glsl view and game engine.

Patch #35197 by Tyler Seacrest.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56484 954f8c5b-7b00-dc11-b283-0030488c597c
Possible fix for #35198: uninitialized memory access with background multiple
importance sampling + OSL.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56485 954f8c5b-7b00-dc11-b283-0030488c597c