[core] Simplify the non-retaining collection implementations.
[core] Simplify the non-retaining collection implementations.

Thanks to @steipete for pointing this out.

SuPair/nimbus,quyixia/nimbus,mohsinalimat/nimbus,kisekied/nimbus,michaelShab/nimbus,quyixia/nimbus,LcongGitHub/nimbus,veue/nimbus,andaluz/nimbus,Guokr1991/nimbus,WeeTom/nimbus,Arcank/nimbus,Guokr1991/nimbus,xiaohongjun0509/nimbus,mohsinalimat/nimbus,djMax/nimbus,Arcank/nimbus,treejames/nimbus,zilaiyedaren/nimbus,zilaiyedaren/nimbus,veue/nimbus,weiyanwu1984/nimbus,chanffdavid/nimbus,xiaohongjun0509/nimbus,DreamHill/nimbus,bogardon/nimbus,LcongGitHub/nimbus,tranhieutt/nimbus,quyixia/nimbus,xiaohongjun0509/nimbus,WeeTom/nimbus,mohsinalimat/nimbus,ycaihua/nimbus,pilot34/nimbus_fork,zaichang/nimbus,chanffdavid/nimbus,michaelShab/nimbus,dachaoisme/nimbus,liuwu/nimbus,jverkoey/nimbus,SuPair/nimbus,DreamHill/nimbus,kisekied/nimbus,0xced/nimbus,kviksilver/nimbus,xiaohongjun0509/nimbus,zilaiyedaren/nimbus,panume/nimbus,michaelShab/nimbus,ycaihua/nimbus,jverkoey/nimbus,liuwu/nimbus,Guokr1991/nimbus,JyHu/nimbus,dieface/nimbus,WeeTom/nimbus,compositeprimes/nimbus,ycaihua/nimbus,cnbin/nimbus,ycaihua/nimbus,andaluz/nimbus,djMax/nimbus,pilot34/nimbus_fork,dachaoisme/nimbus,dmishe/nimbus,LcongGitHub/nimbus,treejames/nimbus,djMax/nimbus,kviksilver/nimbus,quyixia/nimbus,zilaiyedaren/nimbus,michaelShab/nimbus,treejames/nimbus,dieface/nimbus,DreamHill/nimbus,djMax/nimbus,JyHu/nimbus,pilot34/nimbus_fork,Arcank/nimbus,kisekied/nimbus,DreamHill/nimbus,quyixia/nimbus,panume/nimbus,tranhieutt/nimbus,SuPair/nimbus,Guokr1991/nimbus,marcobgoogle/nimbus,bangquangvn/nimbus,panume/nimbus,dachaoisme/nimbus,michaelShab/nimbus,bangquangvn/nimbus,veue/nimbus,weiyanwu1984/nimbus,DreamHill/nimbus,Arcank/nimbus,WeeTom/nimbus,chanffdavid/nimbus,compositeprimes/nimbus,liuwu/nimbus,LcongGitHub/nimbus,zilaiyedaren/nimbus,0xced/nimbus,dachaoisme/nimbus,panume/nimbus,marcobgoogle/nimbus,dieface/nimbus,panume/nimbus,bangquangvn/nimbus,hanangellove/nimbus,mohsinalimat/nimbus,kviksilver/nimbus,ycaihua/nimbus,tranhieutt/nimbus,marcobgoogle/nimbus,andaluz/nimbus,treejames/nimbus,veue/nimbus,michaelShab/nimbus,liuwu/nimbus,weiyanwu1984/nimbus,hanangellove/nimbus,chanffdavid/nimbus,xiaohongjun0509/nimbus,liuwu/nimbus,treejames/nimbus,JyHu/nimbus,JyHu/nimbus,SuPair/nimbus,WeeTom/nimbus,JyHu/nimbus,compositeprimes/nimbus,panume/nimbus,xiaohongjun0509/nimbus,ycaihua/nimbus,zaichang/nimbus,bogardon/nimbus,weiyanwu1984/nimbus,0xced/nimbus,zaichang/nimbus,WeeTom/nimbus,jverkoey/nimbus,jverkoey/nimbus,dmishe/nimbus,dmishe/nimbus,bangquangvn/nimbus,quyixia/nimbus,Guokr1991/nimbus,liuwu/nimbus,treejames/nimbus,compositeprimes/nimbus,hanangellove/nimbus,hanangellove/nimbus,0xced/nimbus,LcongGitHub/nimbus,zaichang/nimbus,weiyanwu1984/nimbus,bogardon/nimbus,mohsinalimat/nimbus,zaichang/nimbus,andaluz/nimbus,dieface/nimbus,zaichang/nimbus,kisekied/nimbus,jverkoey/nimbus,compositeprimes/nimbus,cnbin/nimbus,cnbin/nimbus,JyHu/nimbus,Arcank/nimbus,compositeprimes/nimbus,tranhieutt/nimbus,kviksilver/nimbus,andaluz/nimbus,JyHu/nimbus,tranhieutt/nimbus,pilot34/nimbus_fork,bogardon/nimbus,tranhieutt/nimbus,bangquangvn/nimbus,dachaoisme/nimbus,mohsinalimat/nimbus,zilaiyedaren/nimbus,kviksilver/nimbus,kisekied/nimbus,djMax/nimbus,jverkoey/nimbus,quyixia/nimbus,marcobgoogle/nimbus,0xced/nimbus,andaluz/nimbus,hanangellove/nimbus,SuPair/nimbus,chanffdavid/nimbus,compositeprimes/nimbus,Arcank/nimbus,0xced/nimbus,djMax/nimbus,jverkoey/nimbus,kviksilver/nimbus,Arcank/nimbus,pilot34/nimbus_fork,SuPair/nimbus,dmishe/nimbus,hanangellove/nimbus,cnbin/nimbus,cnbin/nimbus,marcobgoogle/nimbus,Guokr1991/nimbus,cnbin/nimbus,dachaoisme/nimbus,dieface/nimbus,dmishe/nimbus,pilot34/nimbus_fork,pilot34/nimbus_fork,veue/nimbus,dmishe/nimbus,weiyanwu1984/nimbus,kisekied/nimbus,bangquangvn/nimbus,bogardon/nimbus,LcongGitHub/nimbus,chanffdavid/nimbus,bogardon/nimbus,marcobgoogle/nimbus,bogardon/nimbus,DreamHill/nimbus,dieface/nimbus,marcobgoogle/nimbus