struct symtabs_and_lines -> std::vector<symtab_and_line>

struct symtabs_and_lines -> std::vector<symtab_and_line>

This replaces "struct symtabs_and_lines" with
std::vector<symtab_and_line> in most cases.  This removes a number of
cleanups.

In some cases, the sals objects do not own the sals they point at.
Instead they point at some sal that lives on the stack.  Typically
something like this:

  struct symtab_and_line sal;
  struct symtabs_and_lines sals;

  // fill in sal

  sals.nelts = 1;
  sals.sals = &sal;

  // use sals

Instead of switching those cases to std::vector too, such usages are
replaced by gdb::array_view<symtab_and_line> instead.  This avoids
introducing heap allocations.

gdb/ChangeLog:
2017-09-04  Pedro Alves  <palves@redhat.com>

	* ax-gdb.c (agent_command_1): Use range-for.
	* break-catch-throw.c (re_set_exception_catchpoint): Update.
	* breakpoint.c: Include "common/array-view.h".
	(init_breakpoint_sal, create_breakpoint_sal): Change sals
	parameter from struct symtabs_and_lines to
	array_view<symtab_and_line>.  Adjust.  Use range-for.  Update.
	(breakpoint_sals_to_pc): Change sals parameter from struct
	symtabs_and_lines to std::vector reference.
	(check_fast_tracepoint_sals): Change sals parameter from struct
	symtabs_and_lines to std::array_view.  Use range-for.
	(decode_static_tracepoint_spec): Return a std::vector instead of
	symtabs_and_lines.  Update.
	(create_breakpoint): Update.
	(break_range_command, until_break_command, clear_command): Update.
	(base_breakpoint_decode_location, bkpt_decode_location)
	(bkpt_probe_create_sals_from_location)
	(bkpt_probe_decode_location, tracepoint_decode_location)
	(tracepoint_probe_decode_location)
	(strace_marker_create_sals_from_location): Return a std::vector
	instead of symtabs_and_lines.
	(strace_marker_create_breakpoints_sal): Update.
	(strace_marker_decode_location): Return a std::vector instead of
	symtabs_and_lines.  Update.
	(update_breakpoint_locations): Change struct symtabs_and_lines
	parameters to gdb::array_view.  Adjust.
	(location_to_sals): Return a std::vector instead of
	symtabs_and_lines.  Update.
	(breakpoint_re_set_default): Use std::vector instead of struct
	symtabs_and_lines.
	(decode_location_default): Return a std::vector instead of
	symtabs_and_lines.  Update.
	* breakpoint.h: Include "common/array-view.h".
	(struct breakpoint_ops) <decode_location>: Now returns a
	std::vector instead of returning a symtabs_and_lines via output
	parameter.
	(update_breakpoint_locations): Change sals parameters to use
	gdb::array_view.
	* cli/cli-cmds.c (edit_command, list_command): Update to use
	std::vector and gdb::array_view.
	(ambiguous_line_spec): Adjust to use gdb::array_view and
	range-for.
	(compare_symtabs): Rename to ...
	(cmp_symtabs): ... this.  Change parameters to symtab_and_line
	const reference and adjust.
	(filter_sals): Rewrite using std::vector and standard algorithms.
	* elfread.c (elf_gnu_ifunc_resolver_return_stop): Simplify.
	(jump_command): Update to use std::vector.
	* linespec.c (struct linespec_state) <canonical_names>: Update
	comment.
	(add_sal_to_sals_basic): Delete.
	(add_sal_to_sals, filter_results, convert_results_to_lsals)
	(decode_line_2, create_sals_line_offset)
	(convert_address_location_to_sals, convert_linespec_to_sals)
	(convert_explicit_location_to_sals, parse_linespec)
	(event_location_to_sals, decode_line_full, decode_line_1)
	(decode_line_with_current_source)
	(decode_line_with_last_displayed, decode_objc)
	(decode_digits_list_mode, decode_digits_ordinary, minsym_found)
	(linespec_result::~linespec_result): Adjust to use std::vector
	instead of symtabs_and_lines.
	* linespec.h (linespec_sals::sals): Now a std::vector.
	(struct linespec_result): Use std::vector, bool, and in-class
	initialization.
	(decode_line_1, decode_line_with_current_source)
	(decode_line_with_last_displayed): Return std::vector.
	* macrocmd.c (info_macros_command): Use std::vector.
	* mi/mi-main.c (mi_cmd_trace_find): Use std::vector.
	* probe.c (parse_probes_in_pspace, parse_probes): Adjust to use
	std::vector.
	* probe.h (parse_probes): Return a std::vector.
	* python/python.c (gdbpy_decode_line): Use std::vector and
	gdb::array_view.
	* source.c (select_source_symtab, line_info): Use std::vector.
	* stack.c (func_command): Use std::vector.
	* symtab.h (struct symtabs_and_lines): Delete.
	* tracepoint.c (tfind_line_command, scope_info): Use std::vector.