perf test vfs_getname: Look for alternative line where to collect the pathname

The getname_flags() routine changed recently and thus the place where we
were getting the pathname is not probeable anymore, albeit still
present, so use the next line for that, before:

root@number:/home/acme/git/perf-tools-next# perf test vfs_getname
91: Add vfs_getname probe to get syscall args filenames : FAILED!
93: Use vfs_getname probe to get syscall args filenames : FAILED!
126: Check open filename arg using perf trace + vfs_getname : FAILED!
root@number:/home/acme/git/perf-tools-next#

Now tests 91 and 126 are passing, some more investigation is needed for
test 93, that continues to fail.

Cc: Adrian Hunter <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/tests/shell/lib/probe_vfs_getname.sh

···
 add_probe_vfs_getname() {
 	add_probe_verbose=$1
 	if [ $had_vfs_getname -eq 1 ] ; then
-		line=$(perf probe -L getname_flags 2>&1 | grep -E 'result.*=.*filename;' | sed -r 's/[[:space:]]+([[:digit:]]+)[[:space:]]+result->uptr.*/\1/')
+		result_filename_re="[[:space:]]+([[:digit:]]+)[[:space:]]+result->uptr.*"
+		line=$(perf probe -L getname_flags 2>&1 | grep -E "$result_filename_re=" | sed -r "s/$result_filename_re=/\1/")
+		if [ -z "$line" ] ; then
+			result_aname_re="[[:space:]]+([[:digit:]]+)[[:space:]]+result->aname = NULL;"
+			line=$(perf probe -L getname_flags 2>&1 | grep -E "$result_aname_re=" | sed -r "s/$result_aname_re=/\1/")
+		fi
 		perf probe -q       "vfs_getname=getname_flags:${line} pathname=result->name:string" || \
 		perf probe $add_probe_verbose "vfs_getname=getname_flags:${line} pathname=filename:ustring"
 	fi