perf symbol: Create block_info structure

perf symbol: Create block_info structure

'perf diff' currently can only diff symbols(functions).

We should expand it to diff cycles of individual programs blocks as
reported by timed LBR.  This would allow to identify changes in specific
code accurately.

We need a new structure to maintain the basic block information, such as,
symbol(function), start/end address of this block, cycles. This patch
creates this structure and with some ops.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1561713784-30533-2-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>