Auto merge of #109173 - flba-eb:add-i586-qnx70-target, r=compiler-errors

Add tier 3 no_std x86 support for QNX Neutrino RTOS, version 7.0

This PR adds the target `i586-pc-nto-qnx700`, which targets QNX Neutrino RTOS version 7.0 on x86 32-bit targets.

cc: `@flba-eb` `@gh-tr`

This target falls under the umbrella of Tier 3 QNX Neutrino RTOS support documented in `nto-qnx.md` and previously started with #102701.

Author: bors