fix: configure debug logging in browser (#6210)
fix: configure debug logging in browser (#6210)

The Node debug library uses the `DEBUG` environment variable to
configure what gets logged. Our browser version just logs everything;
this commit changes it to look for `window.__PUPPETEER_DEBUG` and matches the behaviour accordingly:

* If the value is not set, nothing is logged.
* If the value is set to `*` everything is logged.
* If the value is set to a string `foo`, messages with that prefix are
  logged.
* If the value is set to a string ending in `*`, e.g. `foo*`, messages
  with prefixes that start with `foo` are logged.
GoogleChrome/puppeteer,puppeteer/puppeteer,puppeteer/puppeteer,GoogleChrome/puppeteer,GoogleChrome/puppeteer,puppeteer/puppeteer,puppeteer/puppeteer