Avoid re-exporting all of src/utilities by default.

This saves 1.1KB of minified+gzip code, and I believe it aligns with our
goals of consolidating the parts of apollo-utilities that we actually use
into the combined @apollo/client package.

More explanation in this comment:
#5292 (comment)

src/index.ts

@@ -39,4 +39,3 @@ export default ApolloClient;
 
 export * from './cache/core';
 export * from './cache/inmemory';
-export * from './utilities';