Taking kSystemPointerSize into account when determining the maximum
allowed BigInt size accidentally made the limit platform-specific.
This patch chooses a platform-independent constant (1<<30) instead.
Bug: chromium:909614
Change-Id: I4717969bc56e6dd5f1eed70b7e60e621989d0719
Reviewed-on: https://chromium-review.googlesource.com/c/1355625
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57983}
