multiplication regex: Do a golf optimization on a captured alternate match; length-=7

Unfortunately, this is the first length optimization that results in worse performance. Iterating through 1*1=1 to 16*16=256 (all matches and non-matches), it is now 30% slower.
multiplication regex: Do a golf optimization on a captured alternate match; length-=9

This one does not result in any slowdown.
multiplication regex: Do a golf optimization on capture alternate matches; length-=6

This does not result in any slowdown either.
multiplication regex: Do a golf optimization on captured alternate matches; length-=6
multiplication regex: Do a golf optimization on captured alternate matches; length-=7

This results in no change in speed.
multiplication regex: Do a golf optimization on a captured alternate match; length-=7

This results in no change in speed.