syscall: skip an unsupported test case on android

Lookup is not supported on android, and the test
syscall/exec_linux_test.go which relies on it will fail on
android/arm64.

Fixes #27327

Change-Id: I6fdb8992d4634ac7e3689360ff114e9431b5e90c
Reviewed-on: https://go-review.googlesource.com/131995Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/syscall/exec_linux_test.go

@@ -16,6 +16,7 @@ import (
 	"os/exec"
 	"os/user"
 	"path/filepath"
+	"runtime"
 	"strconv"
 	"strings"
 	"syscall"
@@ -524,6 +525,11 @@ func TestAmbientCaps(t *testing.T) {
 		t.Skip("skipping test on Kubernetes-based builders; see Issue 12815")
 	}
 
+	// skip on android, due to lack of lookup support
+	if runtime.GOOS == "android" {
+		t.Skip("skipping test on android; see Issue 27327")
+	}
+
 	caps, err := getCaps()
 	if err != nil {
 		t.Fatal(err)