encoding/xml: use bytes.Clone
encoding/xml: use bytes.Clone

Change-Id: I3218b1e3f8869f579facddb29471df13c835dc66
Reviewed-on: https://go-review.googlesource.com/c/go/+/435281
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@google.com>
Run-TryBot: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@google.com>
Auto-Submit: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>

golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go