The comment says functions return pointers for malloc-ed buffers, but the implementations don't seem like so.
https://github.com/apache/trafficserver/blob/c196db5f0a5b957983351ad51ef360bfc68fbd66/include/tscore/ink_base64.h#L34-L35

Previously, HTTP_NO_CACHE Delivery Services skipped the Mids. With Topologies, a HTTP_NO_CACHE DS could use Mids.

The "no-caching" is done via cache.config. Looking at the config generation, it looks like it should be put on both Edge and Mid cache types. But since it wasn't possible for Mids before, we should add a unit test verifying that Mids and Edges both will get a correct "no-caching"