[PATCH 2/2] Make step act as stepi if no line info (PR26243, PR15314, PR15668)

[Eli Zaretskii]

> From: Pedro Alves <pedro@palves.net>
> Date: Tue, 21 Jul 2020 16:37:37 +0100
> 
> gdb/doc/ChangeLog:
> 
> 	* gdb.texinfo (Continuing and Stepping): Describe that "step"
> 	behaves like "stepi" if there's no line info.
> 
> gdb/ChangeLog:
> 
> 	* NEWS: Mention new "step" and "next" behavior.
> 	* infcmd.c (prepare_one_step): If we have no line info, switch to
> 	"stepi/nexti" mode, regardless of "set step-mode".
> 
> gdb/testsuite/ChangeLog:
> 
> 	* gdb.base/step-symless.exp: Step until the breakpoint is reached.
> 	* gdb.dwarf2/dw2-line-number-zero.exp (test_bkpt): Rename to ...
> 	(test_bkpt_step): ... this.  Add "step_mode" parameter.  Test
> 	stepping after reaching the no-line-info breakpoint.

OK for the documentation parts.

Thanks.