rustc_trans: Fix another windows verbatim path
rustc_trans: Fix another windows verbatim path

This was one last spot where directories were being leaked through with
arguments of the form `\\?\` which neither `ld.exe` nor `gcc.exe` does
understands so the prefix needed to be stripped.

Closes #25072

cllns/rust,carols10cents/rust,GBGamer/rust,sae-bom/rust,reem/rust,philyoon/rust,mdinger/rust,krzysz00/rust,aneeshusa/rust,XMPPwocky/rust,pshc/rust,robertg/rust,KokaKiwi/rust,sae-bom/rust,rohitjoshi/rust,cllns/rust,mvdnes/rust,gifnksm/rust,zubron/rust,omasanori/rust,vhbit/rust,nwin/rust,reem/rust,l0kod/rust,aepsil0n/rust,reem/rust,nwin/rust,jashank/rust,aepsil0n/rust,kwantam/rust,pshc/rust,vhbit/rust,mvdnes/rust,ejjeong/rust,mvdnes/rust,mvdnes/rust,pshc/rust,l0kod/rust,jroesch/rust,andars/rust,philyoon/rust,seanrivera/rust,KokaKiwi/rust,seanrivera/rust,aidancully/rust,victorvde/rust,aepsil0n/rust,mdinger/rust,mvdnes/rust,aepsil0n/rust,graydon/rust,zubron/rust,pshc/rust,gifnksm/rust,nwin/rust,l0kod/rust,sae-bom/rust,seanrivera/rust,jashank/rust,jroesch/rust,philyoon/rust,mihneadb/rust,andars/rust,carols10cents/rust,dwillmer/rust,XMPPwocky/rust,graydon/rust,pelmers/rust,graydon/rust,zachwick/rust,GBGamer/rust,jashank/rust,aidancully/rust,zubron/rust,mihneadb/rust,philyoon/rust,vhbit/rust,kwantam/rust,jroesch/rust,l0kod/rust,vhbit/rust,pshc/rust,cllns/rust,omasanori/rust,aneeshusa/rust,jroesch/rust,rohitjoshi/rust,zubron/rust,carols10cents/rust,dwillmer/rust,kwantam/rust,zachwick/rust,XMPPwocky/rust,omasanori/rust,robertg/rust,pelmers/rust,gifnksm/rust,aneeshusa/rust,nwin/rust,andars/rust,l0kod/rust,reem/rust,graydon/rust,sae-bom/rust,rohitjoshi/rust,graydon/rust,aneeshusa/rust,victorvde/rust,ejjeong/rust,GBGamer/rust,nwin/rust,TheNeikos/rust,GBGamer/rust,gifnksm/rust,jashank/rust,jroesch/rust,mdinger/rust,graydon/rust,mihneadb/rust,pelmers/rust,kwantam/rust,dwillmer/rust,TheNeikos/rust,rohitjoshi/rust,zachwick/rust,pshc/rust,jroesch/rust,zubron/rust,rohitjoshi/rust,krzysz00/rust,carols10cents/rust,robertg/rust,sae-bom/rust,vhbit/rust,XMPPwocky/rust,zachwick/rust,zachwick/rust,nwin/rust,GBGamer/rust,jashank/rust,zubron/rust,KokaKiwi/rust,jashank/rust,aidancully/rust,omasanori/rust,aepsil0n/rust,dwillmer/rust,reem/rust,cllns/rust,aidancully/rust,pelmers/rust,KokaKiwi/rust,victorvde/rust,GBGamer/rust,ejjeong/rust,omasanori/rust,GBGamer/rust,l0kod/rust,krzysz00/rust,mvdnes/rust,XMPPwocky/rust,pshc/rust,robertg/rust,aidancully/rust,cllns/rust,l0kod/rust,ejjeong/rust,dwillmer/rust,pelmers/rust,seanrivera/rust,zachwick/rust,vhbit/rust,ejjeong/rust,mihneadb/rust,jashank/rust,krzysz00/rust,pelmers/rust,gifnksm/rust,GBGamer/rust,omasanori/rust,krzysz00/rust,jroesch/rust,pshc/rust,aidancully/rust,andars/rust,carols10cents/rust,KokaKiwi/rust,dwillmer/rust,mdinger/rust,mdinger/rust,ejjeong/rust,XMPPwocky/rust,dwillmer/rust,dwillmer/rust,krzysz00/rust,aneeshusa/rust,philyoon/rust,victorvde/rust,TheNeikos/rust,carols10cents/rust,rohitjoshi/rust,sae-bom/rust,victorvde/rust,vhbit/rust,victorvde/rust,zubron/rust,mihneadb/rust,jroesch/rust,cllns/rust,aneeshusa/rust,andars/rust,robertg/rust,TheNeikos/rust,jashank/rust,nwin/rust,zubron/rust,kwantam/rust,mdinger/rust,seanrivera/rust,mihneadb/rust,seanrivera/rust,robertg/rust,l0kod/rust,andars/rust,TheNeikos/rust,TheNeikos/rust,kwantam/rust,philyoon/rust,aepsil0n/rust,vhbit/rust,reem/rust,nwin/rust,KokaKiwi/rust,gifnksm/rust