Add config for avoiding JNI refs
Add config for avoiding JNI refs

Summary:
@public

Adds `YogaConfig#avoidGlobalJNIRefs` to control whether nodes created with a config will use weak global JNI refs. Used for experimentation.

Reviewed By: SidharthGuglani

Differential Revision: D14149982

fbshipit-source-id: c777c8b3af2167d96154db5aa6afec1476dac35b

facebook/yoga,facebook/css-layout,facebook/css-layout,facebook/css-layout,facebook/yoga,facebook/yoga,facebook/css-layout,facebook/css-layout,facebook/css-layout,facebook/css-layout,facebook/yoga,facebook/yoga,facebook/yoga,facebook/yoga,facebook/css-layout,facebook/css-layout,facebook/yoga,facebook/yoga,facebook/yoga