Due to a typo, long branches were emitted instead of short branches, and the
code would stop working at all in the situation when long branches must be
emitted. This patche fixes this issue.

TEST=mjsunit/wasm/embenchen/lua_binarytrees
BUG=

Review-Url: https://codereview.chromium.org/2351143002
Cr-Commit-Position: refs/heads/master@{#39552}