src: allow setting a dir for all diagnostic output

Add a flag that allows for the setting of a directory where all
diagnostic output will be written to.
e.g. --redirect-warnings

Refs: https://github.com/nodejs/node/pull/33010#issuecomment-618544792

PR-URL: https://github.com/nodejs/node/pull/33584


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>