native: Remove a bogus assert in net::read
native: Remove a bogus assert in net::read

This assert was likely inherited from some point, but it's not quite valid as a
no-timeout read may enter this loop, but data could be stolen by any other read
after the socket is deemed readable.

I saw this fail in a recent bors run where the assertion was tripped.

jashank/rust,mahkoh/rust,zaeleus/rust,aidancully/rust,cllns/rust,mdinger/rust,nwin/rust,aepsil0n/rust,hauleth/rust,P1start/rust,mvdnes/rust,dwillmer/rust,dwillmer/rust,sae-bom/rust,philyoon/rust,robertg/rust,rohitjoshi/rust,miniupnp/rust,emk/rust,omasanori/rust,aidancully/rust,andars/rust,mdinger/rust,dinfuehr/rust,quornian/rust,untitaker/rust,l0kod/rust,ruud-v-a/rust,jroesch/rust,TheNeikos/rust,zubron/rust,kimroen/rust,l0kod/rust,aneeshusa/rust,barosl/rust,AerialX/rust,sae-bom/rust,rprichard/rust,mihneadb/rust,andars/rust,AerialX/rust,untitaker/rust,GBGamer/rust,KokaKiwi/rust,gifnksm/rust,nwin/rust,philyoon/rust,graydon/rust,mdinger/rust,hauleth/rust,rprichard/rust,reem/rust,jroesch/rust,GBGamer/rust,sae-bom/rust,zubron/rust,ejjeong/rust,rohitjoshi/rust,aidancully/rust,mvdnes/rust,ebfull/rust,omasanori/rust,jashank/rust,KokaKiwi/rust,ejjeong/rust,pelmers/rust,AerialX/rust-rt-minimal,carols10cents/rust,carols10cents/rust,vhbit/rust,AerialX/rust,kimroen/rust,hauleth/rust,krzysz00/rust,ruud-v-a/rust,vhbit/rust,pshc/rust,AerialX/rust-rt-minimal,GBGamer/rust,jashank/rust,quornian/rust,ejjeong/rust,andars/rust,0x73/rust,robertg/rust,jroesch/rust,zaeleus/rust,vhbit/rust,defuz/rust,philyoon/rust,victorvde/rust,untitaker/rust,KokaKiwi/rust,rohitjoshi/rust,ktossell/rust,richo/rust,mvdnes/rust,nwin/rust,dinfuehr/rust,avdi/rust,miniupnp/rust,zubron/rust,omasanori/rust,barosl/rust,AerialX/rust-rt-minimal,defuz/rust,P1start/rust,0x73/rust,pelmers/rust,kwantam/rust,barosl/rust,dwillmer/rust,l0kod/rust,AerialX/rust-rt-minimal,0x73/rust,ebfull/rust,jashank/rust,zachwick/rust,dwillmer/rust,0x73/rust,KokaKiwi/rust,zaeleus/rust,KokaKiwi/rust,cllns/rust,pshc/rust,krzysz00/rust,kwantam/rust,P1start/rust,krzysz00/rust,pshc/rust,graydon/rust,nwin/rust,graydon/rust,omasanori/rust,P1start/rust,pelmers/rust,dwillmer/rust,kwantam/rust,graydon/rust,barosl/rust,richo/rust,graydon/rust,mahkoh/rust,gifnksm/rust,l0kod/rust,l0kod/rust,bombless/rust,miniupnp/rust,GBGamer/rust,mdinger/rust,krzysz00/rust,pshc/rust,TheNeikos/rust,zubron/rust,sae-bom/rust,richo/rust,barosl/rust,mvdnes/rust,P1start/rust,pelmers/rust,aidancully/rust,ktossell/rust,ejjeong/rust,XMPPwocky/rust,GBGamer/rust,miniupnp/rust,reem/rust,carols10cents/rust,reem/rust,philyoon/rust,vhbit/rust,cllns/rust,jroesch/rust,nwin/rust,ruud-v-a/rust,ktossell/rust,andars/rust,0x73/rust,defuz/rust,defuz/rust,jroesch/rust,quornian/rust,AerialX/rust-rt-minimal,cllns/rust,aepsil0n/rust,untitaker/rust,untitaker/rust,miniupnp/rust,dinfuehr/rust,omasanori/rust,XMPPwocky/rust,nwin/rust,victorvde/rust,zaeleus/rust,reem/rust,krzysz00/rust,seanrivera/rust,kimroen/rust,pshc/rust,reem/rust,carols10cents/rust,dwillmer/rust,ebfull/rust,zubron/rust,ktossell/rust,jroesch/rust,mihneadb/rust,mahkoh/rust,mahkoh/rust,robertg/rust,mvdnes/rust,mihneadb/rust,hauleth/rust,rprichard/rust,aneeshusa/rust,mahkoh/rust,rohitjoshi/rust,seanrivera/rust,kwantam/rust,aneeshusa/rust,rohitjoshi/rust,AerialX/rust,pshc/rust,mahkoh/rust,barosl/rust,robertg/rust,kwantam/rust,andars/rust,ruud-v-a/rust,dwillmer/rust,robertg/rust,zubron/rust,emk/rust,seanrivera/rust,ruud-v-a/rust,zachwick/rust,vhbit/rust,jashank/rust,bombless/rust,P1start/rust,l0kod/rust,XMPPwocky/rust,nwin/rust,zubron/rust,hauleth/rust,aepsil0n/rust,ebfull/rust,XMPPwocky/rust,zaeleus/rust,krzysz00/rust,dinfuehr/rust,sae-bom/rust,mdinger/rust,KokaKiwi/rust,ktossell/rust,dinfuehr/rust,aneeshusa/rust,mihneadb/rust,sae-bom/rust,GBGamer/rust,victorvde/rust,seanrivera/rust,gifnksm/rust,seanrivera/rust,mihneadb/rust,XMPPwocky/rust,kimroen/rust,pelmers/rust,andars/rust,quornian/rust,TheNeikos/rust,GBGamer/rust,richo/rust,kwantam/rust,0x73/rust,robertg/rust,ktossell/rust,pshc/rust,defuz/rust,vhbit/rust,gifnksm/rust,quornian/rust,defuz/rust,jashank/rust,philyoon/rust,nwin/rust,emk/rust,bombless/rust,vhbit/rust,rohitjoshi/rust,avdi/rust,l0kod/rust,l0kod/rust,untitaker/rust,zachwick/rust,rprichard/rust,0x73/rust,carols10cents/rust,emk/rust,TheNeikos/rust,GBGamer/rust,avdi/rust,ebfull/rust,ktossell/rust,pshc/rust,emk/rust,gifnksm/rust,ejjeong/rust,aidancully/rust,zaeleus/rust,victorvde/rust,philyoon/rust,graydon/rust,pelmers/rust,emk/rust,aneeshusa/rust,vhbit/rust,avdi/rust,seanrivera/rust,XMPPwocky/rust,zubron/rust,TheNeikos/rust,kimroen/rust,aepsil0n/rust,miniupnp/rust,victorvde/rust,victorvde/rust,zachwick/rust,jashank/rust,AerialX/rust-rt-minimal,quornian/rust,gifnksm/rust,AerialX/rust,aepsil0n/rust,rprichard/rust,bombless/rust-docs-chinese,richo/rust,bombless/rust,miniupnp/rust,barosl/rust,aidancully/rust,aneeshusa/rust,quornian/rust,omasanori/rust,jroesch/rust,rprichard/rust,mdinger/rust,AerialX/rust,kimroen/rust,mihneadb/rust,avdi/rust,bombless/rust,avdi/rust,dwillmer/rust,reem/rust,richo/rust,ruud-v-a/rust,miniupnp/rust,jroesch/rust,aepsil0n/rust,emk/rust,ejjeong/rust,bombless/rust,zachwick/rust,hauleth/rust,zachwick/rust,P1start/rust,jashank/rust,mvdnes/rust,dinfuehr/rust,TheNeikos/rust,kimroen/rust,cllns/rust,ebfull/rust,carols10cents/rust,cllns/rust