Support self parameter typehint

Summary: Allow self to be used as a parameter typehint to indicate the declaring class.

Fixes #3672

Reviewed By: @JoelMarcey

Differential Revision: D1666449

Signature: t1:1666449:1415682530:4bf230195a4834bd786974170ef4d8e1ac474150
Fix closure use var reflection for referenced vars

Summary: Referenced use variables should be returned as references by getStaticVariables

Fixes #3624

Reviewed By: @JoelMarcey

Differential Revision: D1671006

Signature: t1:1671006:1415682061:9d3e13cab2630f09871dd6affd0a7ca0ce0f08bf