flip_test: free FBs after each test run
flip_test: free FBs after each test run

Though the FBs will be freed implicitly at process exit, with the
growing number of test cases it's probably better not to let them
accumulate and free them as soon as we can.

Signed-off-by: Imre Deak <fbd5edba1988036c8923f0cca0cce6ac4811db29@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

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