cmd/vendor/github.com/google/pprof/internal/driver: skip read only dir error on Android

On an android/amd64 emulator, $HOME points to / which is not writable.
Ignore the error in the pprof driver test.

With this, androidtest.sh on android/amd64 and android/386 passes.

Upstream pull request https://github.com/google/pprof/pull/295.

Change-Id: If919d7f44530a977fd044631ad01bac87d32deaa
Reviewed-on: https://go-review.googlesource.com/88817
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

src/cmd/vendor/github.com/google/pprof/internal/driver/fetch_test.go

@@ -412,8 +412,10 @@ func TestHttpsInsecure(t *testing.T) {
 		Symbolize: "remote",
 	}
 	rx := "Saved profile in"
-	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
+	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") ||
+		runtime.GOOS == "android" {
 		// On iOS, $HOME points to the app root directory and is not writable.
+		// On Android, $HOME points to / which is not writable.
 		rx += "|Could not use temp dir"
 	}
 	o := &plugin.Options{