Fix a typo in CompareExchangeStrong()
Fix a typo in CompareExchangeStrong()

Use compare_exchange_strong() instead of compare_exchange_weak(), which
can be spuriously fail on some platforms.

Thanks to Mark Roth to pointing this out!

firebase/grpc,jboeuf/grpc,jboeuf/grpc,muxi/grpc,sreecha/grpc,ejona86/grpc,muxi/grpc,muxi/grpc,sreecha/grpc,ctiller/grpc,sreecha/grpc,pszemus/grpc,grpc/grpc,jboeuf/grpc,jtattermusch/grpc,ctiller/grpc,jboeuf/grpc,jboeuf/grpc,firebase/grpc,pszemus/grpc,jboeuf/grpc,stanley-cheung/grpc,vjpai/grpc,sreecha/grpc,jtattermusch/grpc,firebase/grpc,vjpai/grpc,jtattermusch/grpc,sreecha/grpc,donnadionne/grpc,grpc/grpc,donnadionne/grpc,pszemus/grpc,vjpai/grpc,donnadionne/grpc,muxi/grpc,nicolasnoble/grpc,donnadionne/grpc,vjpai/grpc,grpc/grpc,muxi/grpc,ctiller/grpc,donnadionne/grpc,jtattermusch/grpc,nicolasnoble/grpc,ctiller/grpc,grpc/grpc,grpc/grpc,ejona86/grpc,jtattermusch/grpc,nicolasnoble/grpc,nicolasnoble/grpc,jboeuf/grpc,jtattermusch/grpc,pszemus/grpc,firebase/grpc,nicolasnoble/grpc,firebase/grpc,grpc/grpc,nicolasnoble/grpc,jtattermusch/grpc,jtattermusch/grpc,ejona86/grpc,jboeuf/grpc,ejona86/grpc,donnadionne/grpc,ctiller/grpc,pszemus/grpc,ejona86/grpc,firebase/grpc,ejona86/grpc,firebase/grpc,ctiller/grpc,donnadionne/grpc,ctiller/grpc,firebase/grpc,muxi/grpc,stanley-cheung/grpc,stanley-cheung/grpc,vjpai/grpc,nicolasnoble/grpc,muxi/grpc,vjpai/grpc,muxi/grpc,stanley-cheung/grpc,donnadionne/grpc,stanley-cheung/grpc,stanley-cheung/grpc,sreecha/grpc,pszemus/grpc,firebase/grpc,nicolasnoble/grpc,sreecha/grpc,stanley-cheung/grpc,nicolasnoble/grpc,ctiller/grpc,firebase/grpc,pszemus/grpc,vjpai/grpc,sreecha/grpc,nicolasnoble/grpc,jtattermusch/grpc,stanley-cheung/grpc,stanley-cheung/grpc,ejona86/grpc,sreecha/grpc,pszemus/grpc,ejona86/grpc,jboeuf/grpc,ctiller/grpc,pszemus/grpc,ejona86/grpc,grpc/grpc,vjpai/grpc,vjpai/grpc,grpc/grpc,jtattermusch/grpc,grpc/grpc,pszemus/grpc,jboeuf/grpc,ctiller/grpc,ejona86/grpc,firebase/grpc,jtattermusch/grpc,sreecha/grpc,ctiller/grpc,stanley-cheung/grpc,ctiller/grpc,ejona86/grpc,sreecha/grpc,muxi/grpc,sreecha/grpc,jboeuf/grpc,firebase/grpc,grpc/grpc,donnadionne/grpc,stanley-cheung/grpc,jtattermusch/grpc,vjpai/grpc,donnadionne/grpc,muxi/grpc,grpc/grpc,vjpai/grpc,donnadionne/grpc,nicolasnoble/grpc,grpc/grpc,donnadionne/grpc,jboeuf/grpc,muxi/grpc,stanley-cheung/grpc,vjpai/grpc,muxi/grpc,pszemus/grpc,pszemus/grpc,ejona86/grpc,nicolasnoble/grpc