This reverts CL 189277.

Reason for revert: broke 32-bit builders.

Updates #33902

Change-Id: Ie5f180d0371a90e5057ed578c334372e5fc3a286
Reviewed-on: https://go-review.googlesource.com/c/go/+/192097
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>