Cygwin: /proc/<PID>/maps: print real shared region addresses

Cygwin: /proc/<PID>/maps: print real shared region addresses

So far, the addresses printed for the shared regions of a process
were faked.  The assumption was that the shared regions are always
in the same place in all processes, so we just printed the addresses
of the current process.  This is no safe bet.  The only safe bet is
the address of the cygheap.  So keep track of the addresses in the
cygheap and read the addresses from the cygheap of the observed
processes.  Add output for the shared console.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>