Give core registry libraries public visibility

This is so Donuts can create entirely separate Bazel repositories that
link against the Domain Registry codebase.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=116182448

javatests/com/google/domain/registry/testing/BUILD

@@ -17,6 +17,7 @@ java_library(
         "//java/com/google/domain/registry/env/common/default:WEB-INF/datastore-indexes.xml",
         "//java/com/google/domain/registry/env/common/default:WEB-INF/queue.xml",
     ] + glob(["*.csv"]),
+    visibility = ["//visibility:public"],
     deps = [
         "//java/com/google/common/base",
         "//java/com/google/common/cache",

javatests/com/google/domain/registry/testing/mapreduce/BUILD

@@ -8,6 +8,7 @@ load("//java/com/google/testing/builddefs:GenTestRules.bzl", "GenTestRules")
 java_library(
     name = "mapreduce",
     srcs = glob(["*.java"]),
+    visibility = ["//visibility:public"],
     deps = [
         "//java/com/google/common/base",
         "//java/com/google/common/collect",