lib/drmtest: Retire requests via drop caches after gem_quiescent_gpu
lib/drmtest: Retire requests via drop caches after gem_quiescent_gpu

This helps make sure that the GPU is really quiescent by getting
rid of any residual stuff.

Signed-off-by: Oscar Mateo <8d158a6e9567f59e489595fde938b03d223fe815@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

dlespiau/checkmate-test-igt,tiagovignatti/intel-gpu-tools,erikarn/intel-gpu-tools,rib/intel-gpu-tools,rib/intel-gpu-tools,dlespiau/checkmate-test-igt,erikarn/intel-gpu-tools,dlespiau/checkmate-test-igt,erikarn/intel-gpu-tools,rib/intel-gpu-tools,tiagovignatti/intel-gpu-tools,mv0/intel-gpu-tools,tiagovignatti/intel-gpu-tools,chenxianqin/intel-gpu-tools,chenxianqin/intel-gpu-tools,mv0/intel-gpu-tools,erikarn/intel-gpu-tools,yipdw/intel-gpu-tools,chenxianqin/intel-gpu-tools,mv0/intel-gpu-tools,dlespiau/checkmate-test-igt,yipdw/intel-gpu-tools,rib/intel-gpu-tools,yipdw/intel-gpu-tools,mv0/intel-gpu-tools,yipdw/intel-gpu-tools,chenxianqin/intel-gpu-tools,tiagovignatti/intel-gpu-tools