cpu: enable TestARM64minimalFeatures on darwin/arm64

Go 1.16 renamed the iOS port from darwin/arm64 to ios/arm64 and
darwin/arm64 was repurposed for the macOS ARM64 port (see

Now that Go 1.16 is the oldest supported release, the ios tag can be
used exclusively to detect iOS. Thus, TestARM64minimalFeatures which
ought to run on darwin/arm64 can now be enabled on that platform.

For golang/go#45696

Change-Id: Ic510fbf27dc813832507446201501df58c9f6f31
Reviewed-on: https://go-review.googlesource.com/c/sys/+/353530
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/cpu/cpu_test.go b/cpu/cpu_test.go
index 5f7f843..ba25551 100644
--- a/cpu/cpu_test.go
+++ b/cpu/cpu_test.go
@@ -42,7 +42,7 @@
 func TestARM64minimalFeatures(t *testing.T) {
-	if runtime.GOARCH != "arm64" || (runtime.GOOS == "darwin" || runtime.GOOS == "ios") {
+	if runtime.GOARCH != "arm64" || runtime.GOOS == "ios" {
 	if !cpu.ARM64.HasASIMD {