gyptest does not correctly set up the certificates, provisioning profiles, etc. when running xcode tests on a mac

[GoogleCodeExporter]

Tests fail when project requires provisioning profiles, e.g.

./gyptest.py -f xcode test/ios/gyptest-extension.py 

Code Sign error: No code signing identities found: No valid signing identities 
(i.e. certificate and private key pair) matching the team ID “(null)” were 
found.
CodeSign error: code signing is required for product type 'App Extension' in 
SDK 'iOS 8.2'

Suggested fix is to copy the required files into the temporary HOME directory 
when running on Mac.

Original issue reported on code.google.com by dmpatierno@google.com on 9 Dec 2014 at 12:41