While we do have the _test_de_encode data driven tests for file
definitions, we don't yet have something similar for derived classes of
BER_TLV_IE. This means that TLVs used outside of the filesystem context
(for example, decoding the SELECT/STATUS response, but also eUICC and
other stuff) do not yet have test coverage.
This commit just adds the related test code, but no test data yet.
Related: OS#6317
Change-Id: Ied85f292bb57fde11dc188be84e3384dc3ff1601
