regulators: Create FFDCFile class

Create C++ class for a file that contains FFDC (first failure data
capture) data.

This class is used to store FFDC data in an error log. The FFDC data is
passed t

regulators: Create FFDCFile class

Create C++ class for a file that contains FFDC (first failure data
capture) data.

This class is used to store FFDC data in an error log. The FFDC data is
passed to the error logging system using a file descriptor.

The constructor creates the file and opens it for both reading and
writing. The getFileDescriptor() method returns the file descriptor for
reading/writing the file. The destructor closes and deletes the file.

Also moved the test utility functions makeFileUnRemovable() and
makeFileRemovable() to test_utils.hpp so they can be used by multiple
testcases.

Change-Id: Iddef488a28e83a0df7e7f6955c3217ecb3ec2d51

show more ...