Powerpc fix for gdb.base/ending-run.exp

Powerpc fix for gdb.base/ending-run.exp

The last two tests in gdb.base/ending-run.exp case fail on Powerpc when the
system does not have the needed glibc debug-info files loaded.  In this
case, gdb is not able to determine where execution stopped.  This behavior
looks as follows for the test case:

The next to the last test does a next command when the program is stopped
at the closing bracket for main.  The message printed is:

0x00007ffff7d01524 in ?? () from /lib/powerpc64le-linux-gnu/libc.so.6

which fails to match any of the test_multiple options.

The test then does another next command.  On Powerpc, the
message printed it:

Cannot find bounds of current function

The test fails as the output does not match any of the options for the
gdb_test_multiple.

I checked the behavior on Powerpc to see if this is typical.
I ran gdb on the following simple program as shown below.

#include <stdio.h>
int
main(void)
{
  printf("Hello, world!\n");
  return 0;
}

gdb ./hello_world
<snip the gdb start info>

Type "apropos word" to search for commands related to "word"...
Reading symbols from ./hello_world...
(No debugging symbols found in ./hello_world)
(gdb) break main
Breakpoint 1 at 0x818
(gdb) r

Starting program: /home/carll/hello_world
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/powerpc64le-linux-gnu/libthread_db.so.1".

Breakpoint 1, 0x0000000100000818 in main ()
(gdb) n
Single stepping until exit from function main,
which has no line number information.
Hello, world!
0x00007ffff7d01524 in ?? () from /lib/powerpc64le-linux-gnu/libc.so.6
(gdb) n
Cannot find bounds of current function

So it would seem that the messages seen from the test case are
"normal" output for Powerpc when the debug-info is not available.

The following patch adds the output from Powerpc as an option
to the gdb_test_multiple statement, identifying the output as the expected
output on Powerpc without the needed debug-info files installed.

The patch has been tested on a Power 10 system and an Intel
64-bit system.  No additional regression failures were seen on
either platform.