Remove trailing whitespace in files

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=135386752

javatests/google/registry/testing/DeterministicStringGenerator.java

@@ -27,7 +27,7 @@ import javax.inject.Named;
  * A string generator that produces strings using sequential characters in its alphabet. This is
  * most useful in tests as a "fake" password generator (which would otherwise use
  * {@link RandomStringGenerator}.
- * 
+ *
  * <p>Note that consecutive calls to createString will continue where the last call left off in
  * the alphabet.
  */