Make stats.json on the admin server return valid json

Summary: Can't have two object members with the same key.
fixes facebook/hhvm#3331

I assume this isn't a serious backwards-compatibility break, given every JSON implementation I tried can't read the existing data.

Reviewed By: @bertmaher

Differential Revision: D1685785

Signature: t1:1685785:1416286600:1e264b2917e94df9565aa0ed8f9b8fad31dc67f1
Fix parent::__cOnStRuCt and similar with PHP4 constructors

Summary: Fixes facebook/hhvm#4260

Equivalent bug in PHP5: https://bugs.php.net/bug.php?id=40784 (fixed in 2007)

Reviewed By: @paulbiss

Differential Revision: D1685113

Signature: t1:1685113:1416253624:c07844c8ab21fb0d0dda4b683f9d9b1a72d908f4