Fix gyptest-xcode-env-order for Xcode 5.0.0
Fix gyptest-xcode-env-order for Xcode 5.0.0

The evaluation bug of bare environment variable has been fixed by
Xcode 5.0.0, so do not check for the failure anymore.

BUG=381
R=mark@chromium.org

Review URL: https://codereview.chromium.org/83173004
old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google