perf script: Add --insn-trace for instruction decoding

Add a --insn-trace short hand option for decoding and disassembling
instruction streams for intel_pt. This automatically pipes the output
into the xed disassembler to generate disassembled instructions.  This
just makes this use model much nicer to use.

Before

  % perf record -e intel_pt// ...
  % perf script --itrace=i0ns --ns -F +insn,-event,-period | xed -F insn: -A -64
   swapper 0 [000] 17276.429606186: ffffffff81010486 pt_config ([kernel.kallsyms])    nopl  %eax, (%rax,%rax,1)
   swapper 0 [000] 17276.429606186: ffffffff8101048b pt_config ([kernel.kallsyms])    add $0x10, %rsp
   swapper 0 [000] 17276.429606186: ffffffff8101048f pt_config ([kernel.kallsyms])    popq  %rbx
   swapper 0 [000] 17276.429606186: ffffffff81010490 pt_config ([kernel.kallsyms])    popq  %rbp
   swapper 0 [000] 17276.429606186: ffffffff81010491 pt_config ([kernel.kallsyms])    popq  %r12
   swapper 0 [000] 17276.429606186: ffffffff81010493 pt_config ([kernel.kallsyms])    popq  %r13
   swapper 0 [000] 17276.429606186: ffffffff81010495 pt_config ([kernel.kallsyms])    popq  %r14
   swapper 0 [000] 17276.429606186: ffffffff81010497 pt_config ([kernel.kallsyms])    popq  %r15
   swapper 0 [000] 17276.429606186: ffffffff81010499 pt_config ([kernel.kallsyms])    retq
   swapper 0 [000] 17276.429606186: ffffffff8101063e pt_event_add ([kernel.kallsyms])         cmpl  $0x1, 0x1b0(%rbx)
   swapper 0 [000] 17276.429606186: ffffffff81010645 pt_event_add ([kernel.kallsyms])         mov $0xffffffea, %eax
   swapper 0 [000] 17276.429606186: ffffffff8101064a pt_event_add ([kernel.kallsyms])         mov $0x0, %edx
   swapper 0 [000] 17276.429606186: ffffffff8101064f pt_event_add ([kernel.kallsyms])         popq  %rbx
   swapper 0 [000] 17276.429606186: ffffffff81010650 pt_event_add ([kernel.kallsyms])         cmovnz %edx, %eax
   swapper 0 [000] 17276.429606186: ffffffff81010653 pt_event_add ([kernel.kallsyms])         jmp 0xffffffff81010635
   swapper 0 [000] 17276.429606186: ffffffff81010635 pt_event_add ([kernel.kallsyms])         retq
   swapper 0 [000] 17276.429606186: ffffffff8115e687 event_sched_in.isra.107 ([kernel.kallsyms])       test %eax, %eax

Now:

  % perf record -e intel_pt// ...
  % perf script --insn-trace --xed
  ... same output ...

XED needs to be installed with:

  $ git clone https://github.com/intelxed/mbuild.git mbuild
  $ git clone https://github.com/intelxed/xed
  $ cd xed
  $ ./mfile.py
  $ ./mfile.py examples
  $ sudo ./mfile.py --prefix=/usr/local install
  $ sudo cp obj/examples/xed /usr/local/bin
  $ xed | head -3
  ERROR: required argument(s) were missing
  Copyright (C) 2017, Intel Corporation. All rights reserved.
  XED version: [v10.0-328-g7d62c8c49b7b]
  $

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20180920180540.14039-2-andi@firstfloor.org
[ Fixed up whitespace damage, added the 'mfile.py examples + cp obj/examples/xed ... ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>