perf script: Add 'synth' field for synthesized event payloads

Add a field to display the content the raw_data of a synthesized event.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-22-git-send-email-adrian.hunter@intel.com


[ Resolved conflict with 106dacd8 ("perf script: Support -F brstackoff,dso") ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>