Add QuicHash(Map|Set) as a general-purpose hash map and set, which doesn't gurantee pointer stability. And switch to QuicHashSet in various places.

gfe-relnote: (n/a) Switching data structures. No behavior change.
PiperOrigin-RevId: 308041428
Change-Id: I499959c1744d772b01e050a1ea433cbc76f31e6d
diff --git a/quic/core/legacy_quic_stream_id_manager.h b/quic/core/legacy_quic_stream_id_manager.h
index 1a94905..16daa64 100644
--- a/quic/core/legacy_quic_stream_id_manager.h
+++ b/quic/core/legacy_quic_stream_id_manager.h
@@ -99,7 +99,7 @@
 
   // Set of stream ids that are less than the largest stream id that has been
   // received, but are nonetheless available to be created.
-  QuicUnorderedSet<QuicStreamId> available_streams_;
+  QuicHashSet<QuicStreamId> available_streams_;
 
   QuicStreamId largest_peer_created_stream_id_;
 };