Trivial follow up fix for https://crrev.com/c/1946349 which fixes the
call to length on a half-initialized ScopeInfo. ScopeInfo::length()
looks at the uninitialized fields (i.e. in case of ScopeInfo for module
scopes) and would thus crash.

Bug: chromium:1027475, v8:9938, chromium:1072939
Change-Id: I7e4e81edfbbde25063ab40b8e7807fd70625a8a3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2910773
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74703}