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

tcc.h

@@ -1127,7 +1127,8 @@ ST_DATA Sym *local_label_stack;
 ST_DATA Sym *global_label_stack;
 ST_DATA Sym *define_stack;
 ST_DATA CType char_pointer_type, func_old_type, int_type, size_type;
-ST_DATA SValue vstack[VSTACK_SIZE], *vtop;
+ST_DATA SValue __vstack[1+/*to make bcheck happy*/ VSTACK_SIZE], *vtop;
+#define vstack  (__vstack + 1)
 ST_DATA int rsym, anon_sym, ind, loc;
 
 ST_DATA int const_wanted; /* true if constant wanted */