Fix icutrim build failure when building small-icu on Big-Endian platforms
Fix a build error that occurs when icutrim is run to cut down the ICU locale set on Big-Endian platforms when building with --with-intl=small-icu (which is done by the "make binary" target). This fixes the binary build on POWER platforms. See https://github.com/nodejs/node/issues/2601 for details of the specific error that shows.
Cc @srl295