src, tools: add check for left leaning pointers

This commit adds a rule to cpplint to check that pointers in the code
base lean to the left and not right, and also fixes the violations
reported.

PR-URL: https://github.com/nodejs/node/pull/21010


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>