Allow cascade to be a slice with a _target discriminator

Fixes #7782

hugofs/glob/glob_test.go

@@ -73,5 +73,14 @@ func TestGetGlob(t *testing.T) {
 	g, err := GetGlob("**.JSON")
 	c.Assert(err, qt.IsNil)
 	c.Assert(g.Match("data/my.json"), qt.Equals, true)
+}
+
+func BenchmarkGetGlob(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_, err := GetGlob("**/foo")
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
 
 }