Add GDB XMethods for shared_ptr and unique_ptr<T[]>

Add GDB XMethods for shared_ptr and unique_ptr<T[]>

	* python/libstdcxx/v6/xmethods.py (UniquePtrGetWorker.__init__): Use
	correct element type for unique_ptr<T[]>.
	(UniquePtrGetWorker._supports, UniquePtrDerefWorker._supports): New
	functions to disable unsupported operators for unique_ptr<T[]>.
	(UniquePtrSubscriptWorker): New worker for operator[].
	(UniquePtrMethodsMatcher.__init__): Register UniquePtrSubscriptWorker.
	(UniquePtrMethodsMatcher.match): Call _supports on the chosen worker.
	(SharedPtrGetWorker, SharedPtrDerefWorker, SharedPtrSubscriptWorker)
	(SharedPtrUseCountWorker, SharedPtrUniqueWorker): New workers.
	(SharedPtrMethodsMatcher): New matcher for shared_ptr.
	(register_libstdcxx_xmethods): Register SharedPtrMethodsMatcher.
	* testsuite/libstdc++-xmethods/unique_ptr.cc: Test arrays.
	* testsuite/libstdc++-xmethods/shared_ptr.cc: New test.

From-SVN: r243688