Without that, it has a few false positives about out-of-bounds array accesses.
Also makes the clang static-analyzer happy.

Original code review from Sven Panne:
https://codereview.chromium.org/790723002/

CQ_INCLUDE_TRYBOTS=tryserver.v8:v8_linux_arm_dbg,v8_linux_arm64_dbg,v8_mac64_dbg,v8_win_compile_dbg,v8_linux_gcc_rel

Review URL: https://codereview.chromium.org/1393023003

Cr-Commit-Position: refs/heads/master@{#31185}