Fix unaligned memory access error inconstant
pool access during relocation.

Change-Id: I960b59b226cc5f212fff4565b2c7694364f2cb54
Reviewed-on: https://chromium-review.googlesource.com/c/1452357Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#59351}