fix: use per test context (#9343)

Instead of GlobalContext use a local context for tests.
Most notably this allows stuff created to be shut down 
when tests using it is done. After PR #9345 9331 CI is 
often running out of memory/time.

cmd/xl-sets_test.go

@@ -17,6 +17,7 @@
 package cmd
 
 import (
+	"context"
 	"os"
 	"path/filepath"
 	"testing"
@@ -64,6 +65,9 @@ func TestCrcHashMod(t *testing.T) {
 // TestNewXL - tests initialization of all input disks
 // and constructs a valid `XL` object
 func TestNewXLSets(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
 	var nDisks = 16 // Maximum disks.
 	var erasureDisks []string
 	for i := 0; i < nDisks; i++ {
@@ -92,7 +96,7 @@ func TestNewXLSets(t *testing.T) {
 		t.Fatalf("Unable to format disks for erasure, %s", err)
 	}
 
-	if _, err := newXLSets(endpoints, storageDisks, format, 1, 16); err != nil {
+	if _, err := newXLSets(ctx, endpoints, storageDisks, format, 1, 16); err != nil {
 		t.Fatalf("Unable to initialize erasure")
 	}
 }
@@ -100,10 +104,13 @@ func TestNewXLSets(t *testing.T) {
 // TestHashedLayer - tests the hashed layer which will be returned
 // consistently for a given object name.
 func TestHashedLayer(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
 	var objs []*xlObjects
 
 	for i := 0; i < 16; i++ {
-		obj, fsDirs, err := prepareXL16()
+		obj, fsDirs, err := prepareXL16(ctx)
 		if err != nil {
 			t.Fatal("Unable to initialize 'XL' object layer.", err)
 		}