For TestLogOpt test case, add loong64 support to test the host
architecture and os.
The Ctz64 is not intrinsified on loong64 for TestIntendedInlining.
Contributors to the loong64 port are:
Weining Lu <luweining@loongson.cn>
Lei Wang <wanglei@loongson.cn>
Lingqin Gong <gonglingqin@loongson.cn>
Xiaolin Zhao <zhaoxiaolin@loongson.cn>
Meidan Li <limeidan@loongson.cn>
Xiaojuan Zhai <zhaixiaojuan@loongson.cn>
Qiyuan Pu <puqiyuan@loongson.cn>
Guoqi Chen <chenguoqi@loongson.cn>
This port has been updated to Go 1.15.6:
https://github.com/loongson/go