Test adapted from the mips64 test.

Fixes #15454.

Change-Id: If890c2d18a4a03a08faaa2e674edd7223af60290
Reviewed-on: https://go-review.googlesource.com/22472
Run-TryBot: Michael Munday <munday@ca.ibm.com>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>