Rollup merge of #137324 - flba-eb:rename_qnx_target_name_i586, r=workingjubilee

Make x86 QNX target name consistent with other Rust targets

Rename target to be consistent with other Rust targets: Use `i686` instead of `i586`
See also
- #136495
- #109173

CC: `@jonathanpallant` `@japaric` `@gh-tr` `@samkearney`

Author: workingjubilee