big_op: weaken all Absorbing conditions using TCOr and Affine

For all big_op lemmas which had an `Absorbing` condition, the condition
has now become an alternative between `Affine` and `Absorbing`. Thus the
lemmas are made more general. This is spreading the use of the `TCOr
(Affine _) (Absorbing _)` pattern.
2 jobs for !757 with glen/big_op-TCOr-Affine in 16 minutes and 37 seconds (queued for 4 seconds)
merge request