Repair bounds-checking more, this time `tcc -b -run tcc.c -run tcc.c -run tcctest...

Repair bounds-checking more, this time `tcc -b -run tcc.c -run tcc.c -run tcctest.c` works

Hello up there. On the list Grischka made a point that we can't recommend using
-b as long as tcc -b tcc.c doesn't produce anything useful. Now it does, so
please don't treat -b mode as second class citizen anymore.

Thanks,
Kirill

* bcheck2:
  tests: Add tests for compile/run tcc.c with `tcc -b` then compile tcc.c again, then run tcctest.c
  lib/bcheck: Fix code typo in __bound_delete_region()
  lib/bcheck: Don't assume heap goes right after bss
  Make tcc work after self-compiling with bounds-check enabled