Parallel.For hangs

The following minimal example compiles and runs fine with Delphi XE5 and OTL 3.04:

```Delphi
program test;
{$APPTYPE CONSOLE}
uses
sysutils, otlparallel;
type
EMyException = class(Exception);
begin
try
Parallel.Join(
procedure
begin
WriteLn('Starting...');
raise EMyException.Create('Error Message');
end,
procedure
begin
WriteLn('Starting...');
raise EMyException.Create('Error Message');
end).Execute;
finally
WriteLn('Done');
end;
end.
```

It outputs, expectedly:

Starting...
Starting...
Done
Exception EJoinException in module test.exe at 00141E1A.
Error Message;
Error Message.

However, the following (equivalent) code hangs:

```Delphi
program test;
{$APPTYPE CONSOLE}
uses
sysutils, otlparallel;
type
EMyException = class(Exception);
begin
try
Parallel.For(0, 1).
Execute(
procedure(i: Integer)
begin
WriteLn('Starting...');
raise EMyException.Create('Error Message');
end);
finally
WriteLn('Done');
end;
end.
```