This commit adds python script to parse CoreSight tracing event and
print out source line and disassembly, it generates readable program
execution flow for easier humans inspecting.

The script receives CoreSight tracing packet with below format:

                +------------+------------+------------+
  packet(n):    |    addr    |    ip      |    cpu     |
                +------------+------------+------------+
  packet(n+1):  |    addr    |    ip      |    cpu     |
                +------------+------------+------------+

packet::addr presents the start address of the coming branch sample, and
packet::ip is the last address of the branch smple.  Therefore, a code
section between branches starts from packet(n)::addr and it stops at
packet(n+1)::ip.  As results we combines the two continuous packets to
generate the address range for instructions:

  [ sample(n)::addr .. sample(n+1)::ip ]

The script supports both objdump or llvm-objdump...