inspector: use script name for target title

Changes inspector integration to use Node.js script file name as target
title (reported in JSON and shown in developer tools UIs). It will also
report file:// URL for the script as some tools seem to use that field
to open the script in the editor.

PR-URL: https://github.com/nodejs/node/pull/8243


Reviewed-By: bnoordhuis - Ben Noordhuis <info@bnoordhuis.nl>