Enforce currency consistency for server status billing cost

Also adds tests for currency consistency for other costs, and cleans
up some of the testing for negative currencies (since I was there).
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=120231198

javatests/com/google/domain/registry/tools/CreateTldCommandTest.java

@@ -165,6 +165,7 @@ public class CreateTldCommandTest extends CommandTestCase<CreateTldCommand> {
         "--create_billing_cost=\"JPY 12345\"",
         "--restore_billing_cost=\"JPY 67890\"",
         "--initial_renew_billing_cost=\"JPY 101112\"",
+        "--server_status_change_cost=\"JPY 97865\"",
         "--roid_suffix=Q9JYB4C",
         "xn--q9jyb4c");
     Registry registry = Registry.get("xn--q9jyb4c");