The user stack dump feature was recently added for powerpc. But there
was no test case available to test it.

This test works same as on other architectures by preparing a stack
frame on the perf test thread and comparing each frame by unwinding it.

  $ ./perf test 50
    50: Test dwarf unwind    : Ok

User stack dump for powerpc: https://lkml.org/lkml/2016/4/28/482Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1474267100-31079-1-git-send-email-ravi.bangoria@linux.vnet.ibm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>