net/http/pprof: skip TestDeltaProfile on openbsd/arm

It is observed to be flaky on the only openbsd/arm builder.
Skipping on that platform until someone can investigate.

For #50218

Change-Id: Id3a6dc12b93b3cec67870d8d81bd608c4589c952
Reviewed-on: https://go-review.googlesource.com/c/go/+/372794
Trust: Bryan Mills <[email protected]>
Run-TryBot: Bryan Mills <[email protected]>
Reviewed-by: Hyang-Ah Hana Kim <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: Bryan C. Mills

src/net/http/pprof/pprof_test.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"fmt"
 	"internal/profile"
+	"internal/testenv"
 	"io"
 	"net/http"
 	"net/http/httptest"
@@ -152,6 +153,10 @@ func mutexHog(duration time.Duration, hogger func(mu1, mu2 *sync.Mutex, start ti
 }
 
 func TestDeltaProfile(t *testing.T) {
+	if runtime.GOOS == "openbsd" && runtime.GOARCH == "arm" {
+		testenv.SkipFlaky(t, 50218)
+	}
+
 	rate := runtime.SetMutexProfileFraction(1)
 	defer func() {
 		runtime.SetMutexProfileFraction(rate)