Make syzyasan_rtl compile in 64 bit

syzygy/agent/asan/runtime.h

Index: syzygy/agent/asan/runtime.h
diff --git a/syzygy/agent/asan/runtime.h b/syzygy/agent/asan/runtime.h
index 205bee8759553beb1471198316b7e3d169633d2f..2336e82a3cdc41ac4e93c774328f47e38866c4e0 100644
--- a/syzygy/agent/asan/runtime.h
+++ b/syzygy/agent/asan/runtime.h
@@ -317,7 +317,7 @@ class AsanRuntime {
   // The set of thread IDs that have been seen in the current process.
   // This is used to validate thread IDs in a block trailer.
   base::Lock thread_ids_lock_;
-  base::hash_set<uint32_t> thread_ids_;  // Under thread_ids_lock_.
+  std::unordered_set<uint32_t> thread_ids_;  // Under thread_ids_lock_.
 
   // A random key that is generated on object creation. This is used for
   // correlating duplicate crash reports on the back-end.