Remove "noerror" parameter from some TUI functions

Remove "noerror" parameter from some TUI functions

A few TUI functions take a "noerror" parameter.  This is only checked
in one spot: in tui_set_source_content, if noerror is false, and if an
error occurs, then the function will call print_sys_errmsg.

This seems misguided to me, so this patch removes that code and this
parameter.

gdb/ChangeLog
2019-08-16  Tom Tromey  <tom@tromey.com>

	* tui/tui-winsource.h (tui_update_source_window)
	(tui_update_source_window_as_is): Remove "noerror" parameter.
	* tui/tui-winsource.c (tui_update_source_window)
	(tui_update_source_window_as_is): Remove "noerror" parameter.
	(tui_update_source_windows_with_addr)
	(tui_update_source_windows_with_line)
	(tui_source_window_base::rerender)
	(tui_source_window_base::refill): Update.
	* tui/tui-source.h (tui_set_source_content)
	(tui_show_symtab_source): Remove "noerror" parameter.
	* tui/tui-source.c (tui_set_source_content): Remove "noerror"
	parameter.
	(tui_show_symtab_source): Likewise.
	(tui_source_window::maybe_update): Update.
	* tui/tui-disasm.c (tui_show_disassem)
	(tui_show_disassem_and_update_source)
	(tui_disasm_window::do_scroll_vertical)
	(tui_disasm_window::maybe_update): Update.