We already replaced most loops with PutOpBytesLit where possible,
do this in a last few places.

Change-Id: I8c90de017810145a12394fa6b887755e9111b22a
Reviewed-on: https://go-review.googlesource.com/102276
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>