If the parser creates a catch scope, the variable is also added to
ordered_variables_ so just always do that.

Otherwise, it's not possible to create a ScopeInfo for that catch scope

R=verwaest@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2278963002
Cr-Commit-Position: refs/heads/master@{#38921}