fix: drop databases after sample tests (#1401)

There was a bug on dropping databases / deleting backups after the
sample tests where we were trying to delete in the regional instance
first and if an exception was thrown, we would try to delete on the
second instance. This did not work, because the delete / drop operations
do not fail if the database / backup are not found in the instance, the
call simply returns.

In this PR we have applied both deletes one after the other to fix the
issue, instead of relying on the exceptions.

Author: thiagotnunes

samples/snippets/src/test/java/com/example/spanner/SampleTestBase.java

@@ -61,30 +61,26 @@ public static void beforeClass() {
   @AfterClass
   public static void afterClass() {
     for (String databaseId : idGenerator.getDatabaseIds()) {
+      System.out.println("Trying to drop " + databaseId);
       try {
+        // If the database is not found, it is ignored (no exception is thrown)
         databaseAdminClient.dropDatabase(instanceId, databaseId);
-      } catch (Exception e1) {
-        try {
-          databaseAdminClient.dropDatabase(multiRegionalInstanceId, databaseId);
-        } catch (Exception e2) {
-          System.out.println(
-              "Failed to drop database " + databaseId + " due to " + e2.getMessage()
-                  + ", skipping..."
-          );
-        }
+        databaseAdminClient.dropDatabase(multiRegionalInstanceId, databaseId);
+      } catch (Exception e) {
+        System.out.println(
+            "Failed to drop database " + databaseId + " due to " + e.getMessage() + ", skipping..."
+        );
       }
     }
     for (String backupId : idGenerator.getBackupIds()) {
       try {
+        // If the backup is not found, it is ignored (no exception is thrown)
         databaseAdminClient.deleteBackup(instanceId, backupId);
-      } catch (Exception e1) {
-        try {
-          databaseAdminClient.deleteBackup(multiRegionalInstanceId, backupId);
-        } catch (Exception e2) {
-          System.out.println(
-              "Failed to delete backup " + backupId + " due to " + e2.getMessage() + ", skipping..."
-          );
-        }
+        databaseAdminClient.deleteBackup(multiRegionalInstanceId, backupId);
+      } catch (Exception e) {
+        System.out.println(
+            "Failed to delete backup " + backupId + " due to " + e.getMessage() + ", skipping..."
+        );
       }
     }
     spanner.close();