When a virtual object passes by a store node that updates a field to the existing value, then the object and its state were not copied, which lead to the original object being passed on. 
If then later the store actually modifies and copies the virtual object, this new copy is not passed down the effect chain, so subsequent nodes still refer to the original virtual object and try to update it once new information flows in.
This conflicts with updates on the node that originally created the virtual object, leading to divergence.

Bug: v8:6345
Change-Id: Iab1ce98a60b48478b343eae765c80bdfcb8ba390
Reviewed-on: https://chromium-review.googlesource.com/496267
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45120}