Handle negation of minimum representable integer Negating the minimum representable integer overflows, so it has undefined behavior in C++. Handle this as a special case in the code. BUG=chromium:637050 TEST=angle_unittests Change-Id: Ic6e6d638faddad9b70b5d1637bb4b42ef4f43784 Reviewed-on: https://chromium-review.googlesource.com/390551 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>