Explicit locations: rename "address string"/"addr_string" to "location"

Explicit locations: rename "address string"/"addr_string" to "location"

This patch renames all occurrances of "addr_string" and "address
string" in the breakpoint/linespec APIs.  This will emphasize the
change from address strings used in setting breakpoints (et al) to the
new locations-based API introduced in subsequent patches.

gdb/ChangeLog:

	* breakpoint.h (struct breakpoint_ops) <create_sals_from_address>:
	Renamed to create_sals_from_location.
	<decode_linespec>: Renamed to decode_location.
	Update all callers.
	* breakpoint.c (create_sals_from_address_default): Renamed to ...
	(create_sals_from_location_default): ... this.
	(addr_string_to_sals): Renamed to ...
	(location_to_sals): ... this.
	(decode_linespec_default): Renamed to ...
	(decode_location_default): ... this.
	(base_breakpoint_create_sals_from_address): Renamed to ...
	(base_breakpoint_create_sals_from_location): ... this.
	(bkpt_create_sals_from_address): Renamed to ...
	(bkpt_create_sals_from_location): ... this.
	(bkpt_decode_linespec): Renamed to ...
	(bkpt_decode_location): ... this.
	(bkpt_probe_create_sals_from_address): Renamed to ...
	(bkpt_probe_create_sals_from_location): ... this.
	(tracepoint_create_sals_from_address): Renamed to ...
	(tracepoint_create_sals_from_location): ... this.
	(tracepoint_decode_linespec): Renamed to ...
	(tracepoint_decode_location): ... this.
	(tracepoint_probe_create_sals_from_address): Renamed to ...
	(tracepoint_probe_create_sals_from_location): ... this.
	(tracepoint_probe_decode_linespec): Renamed to ...
	(tracepoint_probe_decode_location): ... this.
	(strace_marker_create_sals_from_address): Renamed to ...
	(strace_marker_create_sals_from_location): ... this.
	(decode_linespec_default): Renamed to ...
	(decode_location_default): ... this.