Propagate exceptions fully when using proc_lib

This makes proc_lib behaves like a normal process as far
as the propagation of exceptions is concerned.

Before this commit, the following difference could be
observed:

  6> spawn_link(fun() -> ssl:send(a,b) end).
  <0.43.0>
  7> flush().
  Shell got {'EXIT',<0.43.0>,
             {function_clause,
              [{ssl,send,[a,b],[{file,"..."},{line,275}]}]}}
  ok

  8> proc_lib:spawn_link(fun() -> ssl:send(a,b) end).
  <0.46.0>
  9> flush().
  Shell got {'EXIT',<0.46.0>,function_clause}

After this commit, we get the following instead:

  3> flush().
  Shell got {'EXIT',<0.61.0>,
             {function_clause,
              [{ssl,send,[a,b],[{file,"..."},{line,275}]},
               {proc_lib,init_p,3,[{file,"..."},{line,232}]}]}}

The stacktrace will show minor differences of course
but the form is now the same as without proc_lib.

The rationale behind this commit is that:

* We now have a single form regardless of how the process
  was started

* We can use the stacktrace to programmatically alter behavior
  (for example an HTTP server identifying problems in input
  decoding to send back a generic 400, or a 500 otherwise)

* We can access the stacktrace to print it somewhere (for
  example an HTTP server could send it back to the client
  when a debug mode is enabled)

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/stdlib/test/gen_statem_SUITE.erl b/lib/stdlib/test/gen_statem_SUITE.erl
index 28f9ab81fe..300baaf1c6 100644
--- a/lib/stdlib/test/gen_statem_SUITE.erl
+++ b/lib/stdlib/test/gen_statem_SUITE.erl
@@ -505,10 +505,10 @@ abnormal2(Config) ->
     {ok,Pid} = gen_statem:start_link(?MODULE, start_arg(Config, []), []),
 
     %% bad return value in the gen_statem loop
-    {{bad_return_from_state_function,badreturn},_} =
+    {{{bad_return_from_state_function,badreturn},_},_} =
 	?EXPECT_FAILURE(gen_statem:call(Pid, badreturn), Reason),
     receive
-	{'EXIT',Pid,{bad_return_from_state_function,badreturn}} -> ok
+	{'EXIT',Pid,{{bad_return_from_state_function,badreturn},_}} -> ok
     after 5000 ->
 	    ct:fail(gen_statem_did_not_die)
     end,
@@ -887,7 +887,7 @@ error_format_status(Config) ->
 	gen_statem:start(
 	  ?MODULE, start_arg(Config, {data,Data}), []),
     %% bad return value in the gen_statem loop
-    {{bad_return_from_state_function,badreturn},_} =
+    {{{bad_return_from_state_function,badreturn},_},_} =
 	?EXPECT_FAILURE(gen_statem:call(Pid, badreturn), Reason),
     receive
 	{error,_,