Update stdarch 5 commits in 815d55c610dab39e92e7c83bf5fd4b7a020b4d46..cfba59fccd90b3b52a614120834320f764ab08d1 2021-11-08 00:58:47 +0000 to 2021-11-19 01:29:04 +0000 - Work-around buggy Intel chips erroneously reporting BMI1/BMI2 support (rust-lang/stdarch#1249) - complete armv8 instructions (rust-lang/stdarch#1256) - Fix i8mm feature with bootstrap compiler. (rust-lang/stdarch#1252) - Fix unused link_name attribute. (rust-lang/stdarch#1251) - Add remaining insturctions (rust-lang/stdarch#1250)