fix(spanner): address review comment on test environment reset order

Author: sakthivelmanii

java-spanner/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockAutoTaggingTest.java

@@ -35,16 +35,16 @@ public class MockAutoTaggingTest extends AbstractMockServerTest {
 
   @Before
   public void setUpProperties() {
-    SpannerOptions.useDefaultEnvironment();
     System.clearProperty("spanner.disable_auto_tagging");
     System.clearProperty("spanner.enable_auto_tagging");
+    SpannerOptions.useDefaultEnvironment();
   }
 
   @After
   public void tearDownProperties() {
-    SpannerOptions.useDefaultEnvironment();
     System.clearProperty("spanner.disable_auto_tagging");
     System.clearProperty("spanner.enable_auto_tagging");
+    SpannerOptions.useDefaultEnvironment();
   }
 
   private Spanner createSpanner(boolean enableAutoTag, String targetPackage) {