tests: add unsupported features detection skeleton

Signed-off-by: Justin Chadwell <me@jedevc.com>

tests/workers/features.go

@@ -0,0 +1,13 @@
+package workers
+
+import (
+	"testing"
+
+	"github.com/moby/buildkit/util/testutil/integration"
+)
+
+var features = map[string]struct{}{}
+
+func CheckFeatureCompat(t *testing.T, sb integration.Sandbox, reason ...string) {
+	integration.CheckFeatureCompat(t, sb, features, reason...)
+}