test: disable expensive query test with race detector

It's _really_ slow. We still test queries under the race detector, this
is just an exhaustive logic test.

test/suite.go

@@ -5,6 +5,8 @@ import (
 	"runtime"
 	"testing"
 
+	detectrace "github.com/ipfs/go-detect-race"
+
 	dstore "github.com/ipfs/go-datastore"
 	query "github.com/ipfs/go-datastore/query"
 )
@@ -13,7 +15,6 @@ import (
 var BasicSubtests = []func(t *testing.T, ds dstore.Datastore){
 	SubtestBasicPutGet,
 	SubtestNotFounds,
-	SubtestCombinations,
 	SubtestPrefix,
 	SubtestOrder,
 	SubtestLimit,
@@ -23,6 +24,13 @@ var BasicSubtests = []func(t *testing.T, ds dstore.Datastore){
 	SubtestBasicSync,
 }
 
+// Only enable the expensive "combinations" test when not running the race detector.
+func init() {
+	if !detectrace.WithRace() {
+		BasicSubtests = append(BasicSubtests, SubtestCombinations)
+	}
+}
+
 // BatchSubtests is a list of all basic batching datastore tests.
 var BatchSubtests = []func(t *testing.T, ds dstore.Batching){
 	RunBatchTest,