Update link-to-wiki generator
Remove TextDecoder feature tests

TextDecoder is not required by PDF.js any more, and the wiki entry has been deleted as well:
https://github.com/mozilla/pdf.js/wiki/Required-Browser-Features/_compare/13ddaa98459236169c1d7969f00fa5610bf7e10f...09aac34e58549698930735bdd10685b9ee54a9ac
Adjust use of chrome.storage.managed for Opera

It turns out that chrome.storage.managed is defined for Opera, so the
previous feature detection method did not work.
streamsPrivate API change.

Since 25 February 2014 (crbug.com/345882)
Merge pull request #5271 from Rob--W/opera-fixes

Opera fixes
Merge pull request #5247 from Rob--W/wiki-test-link-gen

Fix links to wiki subsections and remove TextDecoder feature tests