fix(http-log) do not use a queue when queue_size is 1 (#5323)
fix(http-log) do not use a queue when queue_size is 1 (#5323)

This avoids memory issues with an ever growing queue in Lua memory
when the http-log queue handling is slower than the number of
incoming requests, essentially restoring the pre-queueing behavior
of http-log when queuing settings are not enabled.

Without this patch, running http-log under load (e.g. testing with `wrk`)
displays an ever-increasing memory consumption, up until the Lua VM
panics with an "out of memory" error. With this patch, running the
same test with `wrk` shows stable memory consumption.

We still need to address the memory growth issues for when
queueing is enabled and the flushing is too slow, but for now
this is a useful fix to make the default settings usable.
Kong/kong,Kong/kong,Kong/kong