runtime/pprof: disable TestMorestack on macOS under race detector

This is failing but only under the race detector.
It doesn't really seem fair to expect pprof to find
specific profile events with the race detector slowing
everything down anyway.

Change-Id: I4b353d3d63944c87884d117e07d119b2c7bf4684
Reviewed-on: https://go-review.googlesource.com/c/go/+/294071
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

src/runtime/pprof/pprof_test.go

@@ -11,6 +11,7 @@ import (
 	"context"
 	"fmt"
 	"internal/profile"
+	"internal/race"
 	"internal/testenv"
 	"io"
 	"math/big"
@@ -261,18 +262,13 @@ func parseProfile(t *testing.T, valBytes []byte, f func(uintptr, []*profile.Loca
 // as interpreted by matches, and returns the parsed profile.
 func testCPUProfile(t *testing.T, matches matchFunc, need []string, avoid []string, f func(dur time.Duration)) *profile.Profile {
 	switch runtime.GOOS {
-	case "darwin", "ios":
-		switch runtime.GOARCH {
-		case "arm64":
-			// nothing
-		default:
-			out, err := exec.Command("uname", "-a").CombinedOutput()
-			if err != nil {
-				t.Fatal(err)
-			}
-			vers := string(out)
-			t.Logf("uname -a: %v", vers)
+	case "darwin":
+		out, err := exec.Command("uname", "-a").CombinedOutput()
+		if err != nil {
+			t.Fatal(err)
 		}
+		vers := string(out)
+		t.Logf("uname -a: %v", vers)
 	case "plan9":
 		t.Skip("skipping on plan9")
 	}
@@ -588,6 +584,13 @@ func stackContainsAll(spec string, count uintptr, stk []*profile.Location, label
 }
 
 func TestMorestack(t *testing.T) {
+	if runtime.GOOS == "darwin" && race.Enabled {
+		// For whatever reason, using the race detector on macOS keeps us
+		// from finding the newstack/growstack calls in the profile.
+		// Not worth worrying about.
+		// https://build.golang.org/log/280d387327806e17c8aabeb38b9503dbbd942ed1
+		t.Skip("skipping on darwin race detector")
+	}
 	testCPUProfile(t, stackContainsAll, []string{"runtime.newstack,runtime/pprof.growstack"}, avoidFunctions(), func(duration time.Duration) {
 		t := time.After(duration)
 		c := make(chan bool)