perf test shell: Add 'probe_vfs_getname' shell test

First perf shell test:

  # perf test vfs_getname
  60: Add vfs_getname probe to get syscall args filenames: Ok
  #

In verbose mode:

  # perf test -v vfs_getname
  60: Add vfs_getname probe to get syscall args filenames:
  --- start ---
  test child forked, pid 19146
  Added new event:
    probe:vfs_getname    (on getname_flags:72 with pathname=result->name:string)

  You can now use it in all perf tools, such as:

	  perf record -e probe:vfs_getname -aR sleep 1

  test child finished with 0
  ---- end ----
  Add vfs_getname probe to get syscall args filenames: Ok
  #

And if the vmlinux file is not found:

  # mv ../build/v4.12.0-rc6+/vmlinux ../build/v4.12.0-rc6+/vmlinux.hidden
  # perf test vfs_getname
  60: Add vfs_getname probe to get syscall args filenames: Skip
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-8f3n22c1yn516ev30s603ow2@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>