On 32-bit platforms, String::kMaxLength is such that not all BigInts
can be converted to Strings. NoSideEffectsToString, however, used to
assume that this conversion always succeeds. This patch adds a check
for the failure case, and returns "<a very large BigInt>" instead of
crashing.
This change is practically unobservable, because actually formatting
such a huge BigInt to String would take "forever", which is also why
there is no regression test.

Bug: chromium:876628
Change-Id: I1eacdc1cce753ac5d9ca66e61e479043ab576e07
Reviewed-on: https://chromium-review.googlesource.com/1194004Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55491}