LLVM 3.5: added a separate piglit reference file for LLVM 3.5 as it has
an additional passing test
Fix the image memory leak (among another one) in the basic device
driver also.
Check for 'basic' device instead of 'pthread' as that should be always working on any platform.
test_shuffle:

Vectors of size 3 need 4 elements of space in the buffer.
This caused illegal memory accesses in the 'basic' device with
the {u}long cases.

Do not use rand() stimuli due to indeterminism.