Delete MultiplyingCloudDnsWriter

Now that the large zone re-signing test is complete, we no longer need it.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=199507075

java/google/registry/dns/BUILD

@@ -27,8 +27,8 @@ java_library(
         "//java/google/registry/request/auth",
         "//java/google/registry/request/lock",
         "//java/google/registry/util",
+        "//third_party/java/appengine:appengine-api",
         "//third_party/objectify:objectify-v4_1",
-        "@com_google_appengine_api_1_0_sdk",
         "@com_google_auto_value",
         "@com_google_code_findbugs_jsr305",
         "@com_google_dagger",

java/google/registry/dns/writer/clouddns/CloudDnsWriterModule.java

@@ -59,7 +59,6 @@ public abstract class CloudDnsWriterModule {
   @IntoMap
   @StringKey(CloudDnsWriter.NAME)
   abstract DnsWriter provideWriter(CloudDnsWriter writer);
-
   @Provides
   @IntoSet
   @Named("dnsWriterNames")