Make dwarf_stack_value::in_stack_memory a bool

Make dwarf_stack_value::in_stack_memory a bool

Replace int with bool, because that's what it is.

gdb/ChangeLog:

	* dwarf2expr.h (dwarf_expr_piece) <v.mem.in_stack_memory>:
	Change type to bool.
	(dwarf_stack_value) <in_stack_memory>: Likewise.
	(dwarf_expr_context) <push_address>: Change parameter type to
	bool.
	<fetch_in_stack_memory>: Change return type to bool.
	<push>: Change parameter type to bool.
	* dwarf2expr.c (dwarf_expr_context::push): Change parameter type
	to bool.
	(dwarf_expr_context::push_address): Likewise.
	(dwarf_expr_context::fetch_in_stack_memory): Change return type
	to bool.
	(dwarf_expr_context::execute_stack_op): Adjust.
	* dwarf2loc.c (dwarf2_evaluate_loc_desc_full): Adjust.