HHVM 3.25.2, HHVM 3.24.6, and 3.21.10 (CVE-2018-6334)

These releases contains several bugfixes:

• CVE-2018-6334: ability to override global variables and members of $GLOBALS via file uploads
• Linux packaging: fix a regression in our packaging environment that prevented our binary packages from using system time zone databases
• Mac packaging: add support for the system time zone database
• 3.25 and 3.24: stop raising incorrect warnings about PHP4-style constructors in interfaces