7130404: [macosx] "os.arch" value should be "x86_64" for compatibility with Apple JDK6
Summary: On Mac OS X, align system property "os.arch" with Apple legacy JDKs. Also, improve os.name string matching by using .contains() method instead of .startsWith(). This fix spans multiple repositories.
Reviewed-by: dcubed, phh, ohair, katleman