Clean up test directory

test/bg/exact/h/center

test/bg/exact/h/fill

test/bg/exact/h/in

test/bg/exact/h/max

test/bg/exact/h/scale

test/bg/exact/h/tile

test/bg/exact/in

test/bg/exact/out

test/bg/exact/w/center

test/bg/exact/w/fill

test/bg/exact/w/in

test/bg/exact/w/max

test/bg/exact/w/scale

test/bg/exact/w/tile

test/bg/large/h/center

test/bg/large/h/fill

test/bg/large/h/in

test/bg/large/h/max

test/bg/large/h/scale

test/bg/large/h/tile