gdb, gdbsupport: add debug_prefixed_printf, remove boilerplate functions

gdb, gdbsupport: add debug_prefixed_printf, remove boilerplate functions

The *_debug_print_1 functions are all very similar, the only difference
being the subsystem name.  Remove them all and make the logging macros
use a new debug_prefixed_printf function directly.

gdb/ChangeLog:

	* infrun.c (infrun_debug_printf_1): Remove.
	(displaced_debug_printf_1): Remove.
	(stop_all_threads): Use debug_prefixed_printf.
	* infrun.h (infrun_debug_printf_1): Remove.
	(infrun_debug_printf): Use debug_prefixed_printf.
	(displaced_debug_printf_1): Remove.
	(displaced_debug_printf): Use debug_prefixed_printf.
	* linux-nat.c (linux_nat_debug_printf_1): Remove.
	(linux_nat_debug_printf): Use debug_prefixed_printf.

gdbsupport/ChangeLog:

	* common-debug.cc (debug_prefixed_printf): New.
	* common-debug.h (debug_prefixed_printf): New declaration.
	* event-loop.cc (event_loop_debug_printf_1): Remove.
	* event-loop.h (event_loop_debug_printf_1): Remove.
	(event_loop_debug_printf): Use debug_prefixed_printf.
	(event_loop_ui_debug_printf): Use debug_prefixed_printf.

Change-Id: Ib323087c7257f0060121d302055c41eb64aa60c6