Remove printfi_filtered and fprintfi_filtered

After seeing Simon's patch, I thought maybe it was finally time to
remove printfi_filtered and fprintfi_filtered, in favor of using the
"%*s" approach to indenting.

In this patch I took the straightforward approach of always adding a
leading "%*s", even when the format already started with "%s", to
avoid the trickier form of:

    printf ("%*s", -indent, string)

Regression tested on x86-64 Fedora 32.
Let me know what you think.

gdb/ChangeLog
2020-12-17  Tom Tromey  <tromey@adacore.com>

	* gdbtypes.c (print_args, dump_fn_fieldlists, print_cplus_stuff)
	(print_gnat_stuff, print_fixed_point_type_info)
	(recursive_dump_type): Update.
	* go32-nat.c (go32_sysinfo, display_descriptor): Update.
	* c-typeprint.c (c_type_print_base_struct_union)
	(c_type_print_base_1): Update.
	* rust-lang.c (rust_internal_print_type): Update.
	* f-typeprint.c (f_language::f_type_print_base): Update.
	* utils.h (fprintfi_filtered, printfi_filtered): Remove.
	* m2-typeprint.c (m2_record_fields): Update.
	* p-typeprint.c (pascal_type_print_base): Update.
	* compile/compile-loc2c.c (push, pushf, unary, binary)
	(do_compile_dwarf_expr_to_c): Update.
	* utils.c (fprintfi_filtered, printfi_filtered): Remove.