lib: simplify several debug() calls

Avoid calling Array.prototype.join() in debug() calls. These
are evaluated on every call, even if the debug() call is a
no-op. This commit replaces the join() calls with the %j
placeholder.

PR-URL: https://github.com/nodejs/node/pull/25241


Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>