PR python/18438

PR python/18438

gdb/ChangeLog:

	* python/py-lazy-string.c (stpy_convert_to_value): Use
	gdbpy_gdb_memory_error not PyExc_MemoryError.
	(gdbpy_create_lazy_string_object): Ditto.

gdb/testsuite/ChangeLog:

	* gdb.python/py-lazy-string.c: New file.
	* gdb.python/py-lazy-string.exp: New file.
	* gdb.python/py-prettyprint.c (lazystring) <len>: New member.
	(main): Update.  Add estring3.
	* gdb.python/py-prettyprint.exp: Add tests for strings at address 0.
	* gdb.python/py-prettyprint.py (pp_ls): Handle length.