inspector: split --cpu-prof-path to --cpu-prof-dir and --cpu-prof-name

To improve the integration of `--cpu-prof` with workers, this patch
splits `--cpu-prof-path` into `--cpu-prof-dir` and `--cpu-prof-name`,
so when a worker is launched from a thread that enables
`--cpu-prof`, if the parent thread sets `--cpu-prof-dir`, then the
profile of both thread would be generated to the specified directory.
If they end up specifying the same `--cpu-prof-name` the behavior
is undefined the last profile will overwritten the first one.

PR-URL: https://github.com/nodejs/node/pull/27306


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>