glsl: Clear the static values of builtin function profiles at release.

glsl: Clear the static values of builtin function profiles at release.

When releasing the builtin functions, we were just freeing the memory,
not telling the builtin function loader that we had freed its memory.
I wish I had done ARB_ES2_compatibility so we had regression testing
of this path.  Fixes segfault on changing video options in nexuiz.