Revert "log: free resources while event loop is running"

This reverts commit 0c3f9b37.

If log_destroy and log_boot use the same fd (STDERR_FILENO), say()
called after say_logger_free() will write to a closed fd. What's worse,
the fd may be reused, in which case say() will write to a completely
unrelated file or socket (maybe a data file!). This is what happened
with flightrec - flightrec finalization info message was written to
an xlog file. Let's move say_logger_free() back to where it belongs -
after other subsystem has been finalized.

Reopens #4450
Needed for https://github.com/tarantool/tarantool-ee/issues/223

NO_DOC=bug fix
NO_TEST=revert
NO_CHANGELOG=unreleased