issue-560: Revert "issue-481: ...

...Replaced test mechanism for distinct address spaces with a more
reliable mechanism"

This reverts commit 5dd53ab6cbf9d98f2d60546835e84785a104da46 (svn
revision 167)

With this commit rhel 6.2 fails heap-checker-death_unittest and
without it passes.

Ticket refers to 2 things and both are invalid:

* that ptrace PEEKDATA ignores data argument. I've checked kernel
  source and found it to be wrong

* something about distinct address spaces

And in addition to all that original ticket admits that it doesn't fix
anything.

It looks like, compared to original code that "fix" is not succesfully
wait-ing on parent's ptrace request. I.e. by adding some additional
diagnostics I'm seeing this sys_waitpid returning ECHILD.