Currently we only generate addresses in the range 2GiB to 4GiB, because
of a bug, when running in 64-bit mode. With this fix we now use the full
range 2GiB to 4096GiB.

BUG=v8:3997
LOG=n
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/1051303003

Cr-Commit-Position: refs/heads/master@{#27610}