/// diffProgram - This method executes the specified module and diffs the
/// output against the file specified by ReferenceOutputFile. If the output
/// is different, 1 is returned. If there is a problem with the code
/// generator (e.g., llc crashes), this will return -1 and set Error.
///
/// diffProgram - This method executes the specified module and diffs the
/// output against the file specified by ReferenceOutputFile. If the output
/// is different, 1 is returned. If there is a problem with the code
/// generator (e.g., llc crashes), this will return -1 and set Error.
///