sumdb: sync change from cmd/go internal package
sumdb: sync change from cmd/go internal package

Copy change in CL 203607 from cmd/go/internal/sumdb to
golang.org/x/mod/sumdb. This just removed an unused parameter. These
packages should be identical (except for imports) before
cmd/go/internal/sumdb is deleted in CL 202698.

Updates golang/go#31761

Change-Id: I1ce96d66bc71ef5c9515b68811049c47dce97765
Reviewed-on: https://go-review.googlesource.com/c/mod/+/204138
Run-TryBot: Jay Conrod <f3fadaedc813344da5ec13b41e26596889cc5baa@google.com>
Reviewed-by: Bryan C. Mills <1c8aad60184261ccede67f5c63a0d2a3bf3c9ff4@google.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

golang/mod,golang/mod