message: Fix stack_decode.py post
  The [backtrace] search regexes required updating.
diff: @@ -25,11 +25,14 @@ AddressList = collections.namedtuple("AddressList", "obj_file addresses")
  # the entire stack trace has been read. End when EOF received.
  def decode_stacktrace_log(input_source):
  traces = {}
  + # Match something like [backtrace]
  + # bazel-out/local-dbg/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:84]
  + backtrace_marker = "\[backtrace\] [^\s]+"
  trace_begin_re = re.compile(
  - "^(.+)\[backtrace\] Backtrace obj<(.+)> thr<(\d+)")
  - stackaddr_re = re.compile("\[backtrace\] thr<(\d+)> #\d+ (0x[0-9a-fA-F]+)$")
  - new_object_re = re.compile("\[backtrace\] thr<(\d+)> obj<(.+)>$")
  - trace_end_re = re.compile("\[backtrace\] end backtrace thread (\d+)")
  + "^(.+)%s Backtrace obj<(.+)> thr<(\d+)" % backtrace_marker)
  + stackaddr_re = re.compile("%s thr<(\d+)> #\d+ (0x[0-9a-fA-F]+)$" % backtrace_marker)
  + new_object_re = re.compile("%s thr<(\d+)> obj<(.+)>$" % backtrace_marker)
  + trace_end_re = re.compile("%s end backtrace thread (\d+)" % backtrace_marker)
  # build a dictionary indexed by thread_id, value is a Backtrace namedtuple
  try:
  