Auto merge of #106774 - Nugine:master, r=Amanieu

Stabilize cmpxchg16b_target_feature

Tracking issue for target features
+ #44839

stdarch issue
+ rust-lang/stdarch#827

stdarch PR
+ rust-lang/stdarch#1358

reference PR
+ rust-lang/reference#1331

It's my first time contributing to rust-lang/rust. Please tell me if I missed something.

Author: bors