gdb: add infrun_debug_printf macro

gdb: add infrun_debug_printf macro

Introduce this macro to print debug statements in the infrun.c file,
same idea as what was done in 9327494e0eeb ("gdb: add
linux_nat_debug_printf macro").

Although in this case, there are places outside infrun.c that print
debug statements if debug_infrun is set.  So the macro has to be
declared in the header file, so that it can be used in these other
files.

Note one special case.  In stop_all_threads, I've used an explicit

    if (debug_infrun)
      infrun_debug_printf_1 ("stop_all_threads", "done");

for the message in the SCOPE_EXIT.  Otherwise, the message appears like
this:

  [infrun] operator(): done

Until we find a better solution for extracting a meaningful function
name for lambda functions, I think it's fine to handle these special
cases manually, they are quite rare.

Some tests need to be updated, because they rely on some infrun debug
statements.

gdb/ChangeLog:

	* infrun.h (infrun_debug_printf_1): New function declaration.
	(infrun_debug_printf): New macro.
	* infrun.c (infrun_debug_printf_1): Use infrun_debug_printf
	throughout.
	(infrun_debug_printf): New function.
	* breakpoint.c (should_be_inserted): Use infrun_debug_printf.
	(handle_jit_event): Likewise.

gdb/testsuite/ChangeLog:

	* gdb.base/gdb-sigterm.exp (do_test): Update expected regexp.
	* gdb.threads/signal-while-stepping-over-bp-other-thread.exp:
	Likewise.
	* gdb.threads/stepi-random-signal.exp: Likewise.

Change-Id: I66433c8a9caa64c8525ab57c593022b9d1956d5c