Remove unnecessary "throws" declarations

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=201058582

javatests/google/registry/testing/SystemPropertyRule.java

@@ -76,7 +76,7 @@ public final class SystemPropertyRule extends ExternalResource {
   }
 
   @Override
-  protected void before() throws Exception {
+  protected void before() {
     checkState(!isRunning);
     for (Property pending : pendings) {
       pending.set();