Currently gctrace and gcpacertrace recompute the heap goal for
end-of-cycle information but this is incorrect.
Because both of these traces are printing stats from the previous cycle
in this case, they should print the heap goal at the end of the previous
cycle.
Change-Id: I967621cbaff9f331cd3e361de8850ddfe0cfc099
Reviewed-on: https://go-review.googlesource.com/c/go/+/407138 Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: David Chase <drchase@google.com>