For building v8 using gn on aix_ppc64, linux_s390x and linux_ppc64(both LE and BE).

Also add support for host_byteorder logic which is introduced in -
https://codereview.chromium.org/2815453004/

R=adamk@chromium.org, dpranke@chromium.org, machenbach@chromium.org
BUG=706728

Review-Url: https://codereview.chromium.org/2812173002 .
1 file changed