runtime/pprof: fix proto tests on NetBSD

The proto_test tests are failing on NetBSD:

https://build.golang.org/log/a3a577144ac48c6ef8e384ce6a700ad30549fb78

the failures seem similar to previous failures on Android:

https://build.golang.org/log/b5786e0cd6d5941dc37b6a50be5172f6b99e22f0

The Android failures where fixed by CL 37896. This CL is an attempt
to fix the NetBSD failures with a similar fix.

Change-Id: I3834afa5b32303ca226e6a31f0f321f66fef9a3f
Reviewed-on: https://go-review.googlesource.com/38637Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/runtime/pprof/proto_test.go

@@ -70,7 +70,8 @@ func f2() { f2() }
 // testPCs returns two PCs and two corresponding memory mappings
 // to use in test profiles.
 func testPCs(t *testing.T) (addr1, addr2 uint64, map1, map2 *profile.Mapping) {
-	if runtime.GOOS == "linux" || runtime.GOOS == "android" {
+	switch runtime.GOOS {
+	case "linux", "android", "netbsd":
 		// Figure out two addresses from /proc/self/maps.
 		mmap, err := ioutil.ReadFile("/proc/self/maps")
 		if err != nil {
@@ -91,7 +92,7 @@ func testPCs(t *testing.T) (addr1, addr2 uint64, map1, map2 *profile.Mapping) {
 		addr2 = mprof.Mapping[1].Start
 		map2 = mprof.Mapping[1]
 		map2.BuildID, _ = elfBuildID(map2.File)
-	} else {
+	default:
 		addr1 = uint64(funcPC(f1))
 		addr2 = uint64(funcPC(f2))
 	}