Fixed 0e0 as a value on JSON_parser

Summary: We're using a heavily modified version of Dougles Crockford's JSON parsing library. That library has a bug that fails
to parse 0e0 as a value in an array or an object (as a value). This diff corrects the issue which also fixes a broken zend test

Reviewed By: @JoelMarcey

Differential Revision: D1393793
Fix preOptimize for CheckLoc and AssertLoc

Summary: In preOptimize, we convert CheckLoc/AssertLoc into CheckType/AssertType.
The return value of preOptimize should be the old FramePtr, not the
destination of the new instructions.

Reviewed By: @swtaarrs

Differential Revision: D1399908
Fix bug in insertLocalPhis()

Summary: We added a ldLoc but did not add the corresponding src-type constraint.

Reviewed By: @swtaarrs

Differential Revision: D1399896
Bug fix for JitLoop

Summary: We should add block id to region (instead of trans id).

Reviewed By: @ottoni

Differential Revision: D1399052
Introduce I/O wait enter/exit hooks

Summary: Introduce I/O wait enter/exit hooks, useful for profiling asynchronous
execution.

Reviewed By: @billf

Differential Revision: D1397075
Fix hhhbc for SetElem with non-array bases.

Summary: If the base is not an array or an object implementing ArrayAccess,
SetM pushes a null. This was not being handled correctly hhbbc, and
we were pushing the rhs on stack in these cases.

Reviewed By: @jdelong

Differential Revision: D1383973
Various fixes to access modifiers errors

Summary: HHVM would not error correctly for various error relating to multiple access modifiers on methods and functions. This diff matches the behavior of this to php.

Reviewed By: @ptarjan

Differential Revision: D1398889
Add missing removeKey for flakey option

Reviewed By: @JoelMarcey

Differential Revision: D1400965