Sometimes, multiple CLs being merged that create rules on the same
opcodes can cause the generated file to differ compared to a new
regeneration. This is caused by the fact that rulegen splits
generated functions in chunks of 10 rules per function (to avoid
creating functions that are too big). If two CLs add rules to
the same function, they might cause a generated function to
have more than 10 rules, even though each CL individually didn't
pass this limit.

Change-Id: Ib641396b7e9028f80ec8718746969d390a9fbba9
Reviewed-on: https://go-review.googlesource.com/95795
Run-TryBot: Giovanni Bajo <rasky@develer.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>