The serialize set of microbenchmarks serializes Error.stack of a
prepared set of error objects. When all objects have been serialized,
the benchmark then wrapped around and only accessed the resulting
string properties. This, of course, is a lot faster and benchmark
results are heavily fluctuating when the end is reached.

This CL fixes this by introducing a payload that should be similiar
to the specific workload, which is executed after the end is reached.

R=petermarshall@chromium.org

Bug: v8:8742
Change-Id: I7183d04e7c06af0c16fe3412e902f0d33605bc25
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1524485Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60297}