Revert "Disable test for now."

This reverts commit 0a57b45f83d6aa8876e6e91d0e5b3f62a1690d3f.

Change-Id: I8348fdaa62cc86e3b03466844715397f6601b7c8
diff --git a/tools/libcore_failures.txt b/tools/libcore_failures.txt
index 93e71a7..6d67f84 100644
--- a/tools/libcore_failures.txt
+++ b/tools/libcore_failures.txt
@@ -266,10 +266,5 @@
           "libcore.util.NativeAllocationRegistryTest#testNativeAllocationNoAllocatorAndNoSharedRegistry",
           "libcore.util.NativeAllocationRegistryTest#testNativeAllocationNoAllocatorAndSharedRegistry",
           "libcore.util.NativeAllocationRegistryTest#testNullArguments"]
-},
-{
-  description: "Intermittent failure the libcore team is working on",
-  result: EXEC_FAILED,
-  names: ["ibcore.util.ZoneInfoTest#testReadSerialized"]
 }
 ]