runtime: relax TestMemoryLimitNoGCPercent a bit
It seems to be pretty flaky. I've seen:
retained=
289438024
limit=
268435456
bound=
285212672
Which is ~4MB over the bound.
Not sure why this tends to be darwin-specific, but we'll fix
just darwin for now.
(It isn't quite darwin-only, as it appeared in #66893.
But it is certainly worse on darwin.)
Fixes #73136
Update #66893
Change-Id: If609e909bc6c65c2663dd46b7a9bad4fd291c3da
Reviewed-on: https://go-review.googlesource.com/c/go/+/689315
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>