firefox regressions

USN-4234-1 fixed vulnerabilities in Firefox. The update introduced various
minor regressions. This update fixes the problems.

We apologize for the inconvenience.

Original advisory details:

Multiple security issues were discovered in Firefox. If a user were
tricked in to opening a specially crafted website, an attacker could
potentially exploit these to cause a denial of service, obtain sensitive
information, bypass Content Security Policy (CSP) restrictions, conduct
cross-site scripting (XSS) attacks, or execute arbitrary code.