Rollup merge of #146758 - mati865:amd64_mingw_no_rs_objects, r=petrochenkov

Stop linking rs{begin,end} objects on x86_64-*-windows-gnu

Until now, x86_64-pc-windows-gnu linked `rsbegin.o` and `rsend.o` just like i686-pc-windows-gnu, even though they were no-ops for it. This was likely done for the simplicity back when it was introduced.
Today the things are different and these startup/end objects harm other features, like `build-std`. Given the demotion of i686-pc-windows-gnu from tier 1, there is no point in hurting x86_64-pc-windows-gnu, which remains a tier 1.

The files are still shipped in case downstream crates expect them, as in case of the unmaintained `xargo`.

Fixes rust-lang/rust#146739

Author: matthiaskrgr