Non-racing: exit vs erlang:get_stacktrace

[aronisstav]

Following module produces a warning in 3c15bbb:

-module(stacktrace_vs_exit).

-export([test/0]).

test() ->
  spawn(fun() -> erlang:get_stacktrace() end).

Warning:

Warning: The following pair of instructions is not explicitly marked as non-racing in Concuerror's internals:
  1) exits normally
  2) [] = erlang:get_stacktrace()
 Please notify the developers to add info about this pair.
 Concuerror treats such pairs as racing (--assume_racing). (No other such warnings will appear)

This is necessarily in different processes and should be marked as non-racing.