This fixes RunWasmInterpreter_* tests on big endian mips/ppc/s390.

Change-Id: I4b9b767d0de45004ee1195ac225c6d1027c17a05
Reviewed-on: https://chromium-review.googlesource.com/c/1439517
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59174}