skip pin race test on workers without merge diff support

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

client/pinrace_6731_test.go

@@ -12,6 +12,7 @@ import (
 	"github.com/moby/buildkit/client/llb"
 	gateway "github.com/moby/buildkit/frontend/gateway/client"
 	"github.com/moby/buildkit/util/testutil/integration"
+	"github.com/moby/buildkit/util/testutil/workers"
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/sync/errgroup"
@@ -66,6 +67,7 @@ func init() {
 // custom buildkitd build or env-var instrumentation is needed.
 func testPinRaceIgnoreCacheShift(t *testing.T, sb integration.Sandbox) {
 	integration.SkipOnPlatform(t, "windows")
+	workers.CheckFeatureCompat(t, sb, workers.FeatureMergeDiff)
 
 	const fetchDelay = 1500 * time.Millisecond
 	const headStart = 400 * time.Millisecond

util/testutil/workers/dockerd.go

@@ -33,6 +33,7 @@ func InitDockerdWorker() {
 			FeatureCacheBackendS3,
 			FeatureDirectPush,
 			FeatureImageExporter,
+			FeatureMergeDiff,
 			FeatureMultiCacheExport,
 			FeatureMultiPlatform,
 			FeatureOCIExporter,