Introduced in rB9916e0193c36: New Transform 3D view recalculate scheme.,
TREDRAW_SOFT has been implemented to avoid recalculating the transform
on events where this is not required.

However, this solution seems to work (at least not anymore).
This is because even if the flag assigned is just TREDRAW_SOFT, the
transform is always recalculated in transformApply.

What happens is that the TREDRAW_SOFT flag, when alone, is not cleared
in transformApply and therefore is used in the drawTransformApply
callback which basically recalculates the transformation which finally
clears the flag.

So TREDRAW_SOFT seems useless.

The solution here is to remove that drawTransformApply callback so
transformApply is not called when unnecessary.

(This will also allow us to solve T96728 more elegantly).