Bug 1613571. Align service worker invalid-script-url and invalid-scope-url checks better with the spec. r=dom-workers-and-storage-reviewers,perry

Behavior changes:

1. We now throw a TypeError, not a SecurityError, when the script URI scheme is

not 'http' or 'https', like the spec says to.

2. We now throw when the scope URI scheme is not 'http' or 'https', like the

spec says to.

3. We now throw a proper TypeError, not a DOMException, at the end of

CheckForSlashEscapedCharsInPath.

4. More informative error messages.

Differential Revision: https://phabricator.services.mozilla.com/D61782