Blender Git Loki

Fix T90835: Strip snaps to first and second frame

This was caused by strips with single frame input like single image
strip or color strip. their length is always 1, and so content length
was calculated to end after first frame.

There was code handling this case, but it was also checking for
`anim_endofs` and `endstill` values. Anim offset values have no effect
on these strips and still frame value was used incorrectly. So these
chacks can be removed completely.