JSON encode now detects recursion on array in serializable objects

Summary: fixes #3483
The cause of the problem is that there is no recursion detection for serializable objects, which can lead to a stack overflow.

Also, moved bad zend test bug61978 to good.

Reviewed By: @ptarjan

Differential Revision: D1522715
Remove FramePtr dests from {Assert,Check,Guard,SideExitGuard}Loc.

Summary: They are no longer needed, as IRBuilder tracks type sources by its
GuardConstraints object.

Reviewed By: @ottoni, @swtaarrs

Differential Revision: D1518873