Use implicitly-defined copy operations for test iterators

Use implicitly-defined copy operations for test iterators

All of these special member functions do exactly what the compiler would
do anyway. By defining them as defaulted for C++11 and later we prevent
move constructors and move assignment operators being defined (which is
consistent with the previous semantics).

Also move default init of the input_iterator_wrapper members from the
derived constructor to the protected base constructor.

	* testsuite/util/testsuite_iterators.h (output_iterator_wrapper)
	(input_iterator_wrapper, forward_iterator_wrapper)
	bidirectional_iterator_wrapper, random_access_iterator_wrapper): Remove
	user-provided copy constructors and copy assignment operators so they
	are defined implicitly.
	(input_iterator_wrapper): Initialize members in default constructor.
	(forward_iterator_wrapper): Remove assignments to members of base.

From-SVN: r277459