ftracetest: Add POSIX.3 standard and XFAIL result codes

Add XFAIL and POSIX 1003.3 standard codes (UNRESOLVED/
UNTESTED/UNSUPPORTED) as result codes. These are used for the
results that test case is expected to fail or unsupported
feature (by config).

To return these result code, this introduces exit_unresolved,
exit_untested, exit_unsupported and exit_xfail functions,
which use real-time signals to notify the result code to
ftracetest.

This also set "errexit" option for the testcases, so that
the tests don't need to exit explicitly.

Note that if the test returns UNRESOLVED/UNSUPPORTED/FAIL,
its test log including executed commands is shown on console
and main logfile as below.

------
# ./ftracetest samples/
=== Ftrace unit tests ===
[1] failure-case example [FAIL]
execute: /home/fedora/ksrc/linux-3/tools/testing/selftests/ftrace/samples/fail.tc
+ . /home/fedora/ksrc/linux-3/tools/testing/selftests/ftrace/samples/fail.tc
++ cat non-exist-file
cat: non-exist-file: No such file or directory
[2] pass-case example [PASS]
[3] unresolved-case example [UNRESOLVED]
execute: /home/fedora/ksrc/linux-3/tools/testing/selftests/ftrace/samples/unresolved.tc
+ . /home/fedora/ksrc/linux-3/tools/testing/selftests/ftrace/samples/unresolved.tc
++ trap exit_unresolved INT
++ kill -INT 29324
+++ exit_unresolved
+++ kill -s 38 29265
+++ exit 0
[4] unsupported-case example [UNSUPPORTED]
execute: /home/fedora/ksrc/linux-3/tools/testing/selftests/ftrace/samples/unsupported.tc
+ . /home/fedora/ksrc/linux-3/tools/testing/selftests/ftrace/samples/unsupported.tc
++ exit_unsupported
++ kill -s 40 29265
++ exit 0
[5] untested-case example [UNTESTED]
[6] xfail-case example [XFAIL]

# of passed: 1
# of failed: 1
# of unresolved: 1
# of untested: 1
# of unsupported: 1
# of xfailed: 1
# of undefined(test bug): 0
------

Link: http://lkml.kernel.org/p/20140929120211.30203.99510.stgit@kbuild-f20.novalocal

Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>