Explicit locations: introduce address locations

Explicit locations: introduce address locations

This patch adds support for address locations, of the form "*ADDR".
[Support for address linespecs has been removed/replaced by this "new"
location type.] This patch also converts any existing address locations
from its previous linespec type.

gdb/ChangeLog:

	* breakpoint.c (create_thread_event_breakpoint, init_breakpoint_sal):
	Convert linespec to address location.
	* linespec.c (canonicalize_linespec): Do not handle address
	locations here.
	(convert_address_location_to_sals): New function; contents moved
	from ...
	(convert_linespc_to_sals): ... here.
	(parse_linespec): Remove address locations from linespec grammar.
	Remove handling of address locations.
	(linespec_lex_to_end): Remove handling of address linespecs.
	(event_location_to_sals): Handle ADDRESS_LOCATION.
	(linespec_expression_to_pc): Export.
	* linespec.h (linespec_expression_to_pc): Add declaration.
	* location.c (struct event_location.u) <address>: New member.
	(new_address_location, get_address_location): New functions.
	(copy_event_location, delete_event_location, event_location_to_string)
	(string_to_event_location, event_location_empty_p): Handle address
	locations.
	* location.h (enum event_location_type): Add ADDRESS_LOCATION.
	(new_address_location, get_address_location): Declare.
	* python/py-finishbreakpoint.c (bpfinishpy_init): Convert linespec
	to address location.
	* spu-tdep.c (spu_catch_start): Likewise.