flip_test: add wf-vblank test for expired sequence
flip_test: add wf-vblank test for expired sequence

In v2:
- Wait for the seq that just completed (current_seq) not last_seq - 1.
- Do an equality check for ts and seq instead of >=. The previous
  issue didn't let us do this before.
- Simplify the condition when we do an "expired sequence" check by
  only using the last flip event as a reference.

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

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