Improve small struct deserialization performance by 10%
Improve small struct deserialization performance by 10%

Summary:
Forces inlining of one of the `deserialize` implementations.
Failing to inline the function caused `cursor` object copy using SIMD with Store-to-Load Forwarding block issues

Reviewed By: yfeldblum, vitaut

Differential Revision: D29304849

fbshipit-source-id: 2d3d4bb466114beeb7fc88c694dab7d0df344b07

facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift