This patch introduces a mechanism for changing the scope of temporary
variables, which is necessary for rewriting arrow parameter
initializers.
It also fixes a potential bug in AstExpressionVisitor, which did not
visit the automatically generated members of ForEachStatement.
Fixes test/mjsunit/harmony/regress/regress-4658.js
R=rossberg@chromium.org
BUG=v8:4658
LOG=N
Review URL: https://codereview.chromium.org/1564343002
Cr-Commit-Position: refs/heads/master@{#33183}
