We don't need it anymore, as we're accessing all the field offsets
symbolically.
This won't affect 64-bit, but it makes itabs on 32-bit 4 bytes smaller.
Change-Id: I7fb937813111476fd5ab03005b248ea7bb962cf6
Reviewed-on: https://go-review.googlesource.com/c/go/+/549517 Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>