perf tests: Add platform dependency to test 15

perf tests: Add platform dependency to test 15

This patch adds platform dependency into the test case 15
(perf_event_attr). It is based on a suggestion from Jiri Olsa.

Add a new optional attribute named 'arch' in the [config] section of the
test case file. It is a comma separated list of architecture names this
test can be executed on. For example:

  arch = x86_64,alpha,ppc

If this attribute is missing the test is executed on any platform.  This
does not break existing behavior.

The values listed for this attribute should be identical to uname -m
output.

If the list starts with an exclamation mark (!) the comparison is
inverted, for example for

  arch = !s390x,ppc

the test is not executed on s390x or ppc platforms.  The exclamation
mark must be at the beginnning of the list.

Here is an example debug output:

  [root@s35lp76]# fgrep arch tests/attr/test-stat-C2
  arch = x86_64,alpha,ppc
  [root@s35lp76]# PERF_TEST_ATTR=/tmp /usr/bin/python2 ./tests/attr.py \
    -d ./tests/attr/ -p ./perf -vvvvv -t test-stat-C1

provides the following output:

  running './tests/attr//test-stat-C1'
  test limitation 'x86_64,alpha,ppc' <--- new
    loading expected events
      Event event:base-stat
        fd = 1
        group_fd = -1
        .....

Here is the output when a test is skipped:

  [root@s35lp76]# fgrep arch tests/attr/test-stat-C1
  arch = !s390x
  [root@s35lp76]# PERF_TEST_ATTR=/tmp /usr/bin/python2 ./tests/attr.py \
    -d ./tests/attr/ -p ./perf -vvvvv -t test-stat-C1

provides the following output:

test limitation '!s390x' <--- new

skipped [s390x] './tests/attr//test-stat-C1' <--- new

The test is skipped with return code 0.

Suggested-and-Acked-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/20170622073625.86762-1-tmricht@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>