because that's what it actually does. In the next step, I will
introduce EmitVarInt again with the correct semantics, and use it in
EmitI32Const and other places where we don't do proper varint encoding
currently.

R=bradnelson@chromium.org, titzer@chromium.org

Review-Url: https://codereview.chromium.org/2694633003
Cr-Commit-Position: refs/heads/master@{#43198}