This change also adds an end-to-end test for SetMemoryLimit as a
testprog.
Fixes#48409.
Change-Id: I102d64acf0f36a43ee17b7029e8dfdd1ee5f057d
Reviewed-on: https://go-review.googlesource.com/c/go/+/397018
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
