Increase shards on batch package tests

ExpandRecurringBillingEventsActionTest is occasionally timing out.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=140059399

javatests/google/registry/batch/BUILD

@@ -41,7 +41,7 @@ java_library(
 GenTestRules(
     name = "GeneratedTestRules",
     default_test_size = "medium",
-    shard_count = 3,
+    shard_count = 4,
     test_files = glob(["*Test.java"]),
     deps = [":batch"],
 )