Summary:
@public
Passing primitive data via JNI is more efficient than passing objects.
Here, we avoid creating `YogaValue` (Java) instances via JNI, and rather pass a `long` back to Java. The instance is then created by extracting the necessary bytes on the Java side.
Reviewed By: foghina
Differential Revision: D14576755
fbshipit-source-id: 22d09ad50c3ac6c49b0a797a0dad639ea4829df9