chore(xds): remove unused import

Author: PetitBaguette

xds/src/main/java/io/grpc/xds/XdsNameResolver.java

@@ -73,7 +73,6 @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;