OptimizedFrame::Summarize is used by debugger features etc
to inspect the frame of an optimized function (and the virtual frames
of functions that got inlined). It could end up materializing a JSArray
with the same backing store as one that would later get left-trimmed,
resulting in a dangling elements pointer. This CL fixes that by creating
a fresh copy of the elements store instead.

Bug: chromium:1182647
Change-Id: Iaf329464520a927b0ba33166cad2524d3752c450
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2748593Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73330}