In case of deoptimization after WordCompare test, the control flow is lost in the
unoptimized version of the code because wrong register is used for comparision
(a0 instead of v0)

TEST=mjsunit/regress/regress-3717
BUG=

Review-Url: https://codereview.chromium.org/2160533003
Cr-Commit-Position: refs/heads/master@{#37845}