flip_test: make page flip tests conditional
flip_test: make page flip tests conditional

Since later we want to add vblank tests where we don't want to flip,
make the flips and corresponding state checks conditional.

No functional change.

Signed-off-by: Imre Deak <fbd5edba1988036c8923f0cca0cce6ac4811db29@intel.com>

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