gdb: make type::bounds work for array and string types

gdb: make type::bounds work for array and string types

Getting the bounds of an array (or string) type is a common operation,
and is currently done through its index type:

    my_array_type->index_type ()->bounds ()

I think it would make sense to let the `type::bounds` methods work for
arrays and strings, as a shorthand for this.  It's natural that when
asking for the bounds of an array, we get the bounds of the range type
used as its index type.  In a way, it's equivalent as the now-removed
TYPE_ARRAY_{LOWER,UPPER}_BOUND_IS_UNDEFINED and
TYPE_ARRAY_{LOWER,UPPER}_BOUND_VALUE, except it returns the
`range_bounds` object.  The caller is then responsible for getting the
property it needs in it.

I updated all the spots I could find that could take advantage of this.

Note that this also makes `type::bit_stride` work on array types, since
`type::bit_stride` uses `type::bounds`.  `my_array_type->bit_stride ()`
now returns the bit stride of the array's index type.  So some spots
are also changed to take advantage of this.

gdb/ChangeLog:

	* gdbtypes.h (struct type) <bounds>: Handle array and string
	types.
	* ada-lang.c (assign_aggregate): Use type::bounds on
	array/string type.
	* c-typeprint.c (c_type_print_varspec_suffix): Likewise.
	* c-varobj.c (c_number_of_children): Likewise.
	(c_describe_child): Likewise.
	* eval.c (evaluate_subexp_for_sizeof): Likewise.
	* f-typeprint.c (f_type_print_varspec_suffix): Likewise.
	(f_type_print_base): Likewise.
	* f-valprint.c (f77_array_offset_tbl): Likewise.
	(f77_get_upperbound): Likewise.
	(f77_print_array_1): Likewise.
	* guile/scm-type.c (gdbscm_type_range): Likewise.
	* m2-typeprint.c (m2_array): Likewise.
	(m2_is_long_set_of_type): Likewise.
	* m2-valprint.c (get_long_set_bounds): Likewise.
	* p-typeprint.c (pascal_type_print_varspec_prefix): Likewise.
	* python/py-type.c (typy_range): Likewise.
	* rust-lang.c (rust_internal_print_type): Likewise.
	* type-stack.c (type_stack::follow_types): Likewise.
	* valarith.c (value_subscripted_rvalue): Likewise.
	* valops.c (value_cast): Likewise.

Change-Id: I5c0c08930bffe42fd69cb4bfcece28944dd88d1f