cmd/go: enable fuzz testing on OpenBSD
This change provides support for -fuzz flag on OpenBSD. According to #46554 the flag was unsupported on some OSes due to lack of proper testing.
Fixes: #60491
Change-Id: I49835131d3ee23f6482583b518b9c5c224fc4efe
GitHub-Last-Rev:
f697a3c0f2dc36cc3c96c0336281c5e2440f7a1a
GitHub-Pull-Request: golang/go#60520
Reviewed-on: https://go-review.googlesource.com/c/go/+/499335
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: qiu laidongfeng2 <2645477756@qq.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>