v3.8.4

Version 3.8.4 is a maintenance release with one bug fix and 2 performance improvements. New developments happen in the 4.x versions.

• [java-runtime] Fix ApolloClient.Builder.okHttpClient() returns null instead of this (#5860)
• [normalized-cache] Use a single transaction when using MemoryCache chaining (#5861)
• [normalized-cache] Call through to loadRecords from the MemoryCache to the SQL one (#5863)