Memory leak in 10.5.19 and 10.5.20

We had two fresh installs (one with 10.5.20 and one with 10.5.21) and they both showed signs of a memory leak right away. The server with 10.5.20 installed was going from restart to consuming all available RAM in about 2 hours, linearly, while 10.5.21 was taking about 10 hours. The server using the RAM the fastest had about 3x the query load on it.

We downgraded both servers to 10.5.19 because we have several others on that version that aren't showing memory leaks. These are all sharded servers so they all have similar data and queries happening on them.

The one downgraded from 10.5.21 to 10.5.19 (which had the fastest memory leak before) is now stable, without increasing memory.

However, the one downgraded from 10.5.20 to 10.5.19 continues to have a memory leak and is consuming all of the RAM on the server every 8 hours or so.

The results of `/usr/share/bcc/tools/memleak -o 16000 -T 5 -p 36782` from the server still showing memory leaks is attached. I didn't know about that tool when they were on 10.5.20 and 10.5.21 so I don't have output for those versions.