perf script python: add Python3 support to check-perf-trace.py

perf script python: add Python3 support to check-perf-trace.py

Support both Python 2 and Python 3 in the check-perf-trace.py script.

There may be differences in the ordering of output lines due to
differences in dictionary ordering etc.  However the format within lines
should be unchanged.

The use of from __future__ implies the minimum supported version of
Python2 is now v2.6

Signed-off-by: Tony Jones <tonyj@suse.de>
Cc: Tom Zanussi <tzanussi@gmail.com>
Link: http://lkml.kernel.org/r/20190302011903.2416-4-tonyj@suse.de
Signed-off-by: Seeteena Thoufeek <s1seetee@linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>