lib/bcheck: Fix code typo in __bound_delete_region()
lib/bcheck: Fix code typo in __bound_delete_region()

We were calling get_page() with t2 index which is not correct, since
get_page() operate on t1 indices. The bug is here from day-1, from
60f781c4 (first version of bounds checker) and show as a crash in
__bound_delete_region() at program exit:

    $ ./tcc   -B. -DTCC_TARGET_I386 -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\" -b -run -DONE_SOURCE \
      ./tcc.c -B. -DTCC_TARGET_I386 -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\"    -run -DONE_SOURCE \
      ./tcc.c -B. -run tests/tcctest.c

    (lot's of correct output from tcctest)
    Runtime error: dereferencing invalid pointer
    at 0xa7c21cc4 __bound_delete_region()
    by (nil) ???
    Segmentation fault

The fix is simple - last page should be get through t1_end, like it is
done in __bound_new_region().

After this patch, tcc is being able to compile itself with -b, then
compile itself again and run tcctest with correct output. Tests follow.

acook/tinycc,avih/tinycc,andreiw/tinycc,melkior/tinycc,avih/tinycc,melkior/tinycc,Archs/TinyCC,mingodad/tinycc,Archs/TinyCC,leeduhem/tinycc,seyko2/tinycc,seyko2/tinycc,andrewchambers/tccmirror,rchandramouli/tinycc,metaeducation/tcc,rchandramouli/tinycc,fstudio/tinycc,alfonsokim/tinycc,alfonsokim/tinycc,avih/tinycc,mirror/tinycc,run4flat/tinycc,yousong/tinycc,alfonsokim/tinycc,rchandramouli/tinycc,ftdi-paul-jiao/tinyCC,metaeducation/tcc,andrewchambers/tccmirror,mobiphil/tinnycc,mobiphil/tinnycc,fstudio/tinycc,mingodad/tinycc,rchandramouli/tinycc,FriedBreakfast/tcc,mirror/tinycc,mingodad/tinycc,andrewchambers/tccmirror,acook/tinycc,melkior/tinycc,metaeducation/tcc,mobiphil/tinnycc,Saectar/inherpreter,andrewchambers/tccmirror,leeduhem/tinycc,Saectar/inherpreter,avih/tinycc,leeduhem/tinycc,run4flat/tinycc,mingodad/tinycc,Saectar/inherpreter,ftdi-paul-jiao/tinyCC,code4game/tinycc,leeduhem/tinycc,FriedBreakfast/tcc,ftdi-paul-jiao/tinyCC,melkior/tinycc,gfwilliams/tinycc,Archs/TinyCC,andrewchambers/tccmirror,yousong/tinycc,gfwilliams/tinycc,mobiphil/tinnycc,yousong/tinycc,run4flat/tinycc,alfonsokim/tinycc,Archs/TinyCC,mirror/tinycc,gfwilliams/tinycc,ftdi-paul-jiao/tinyCC,code4game/tinycc,alfonsokim/tinycc,FriedBreakfast/tcc,Saectar/inherpreter,seyko2/tinycc,Archs/TinyCC,seyko2/tinycc,code4game/tinycc,metaeducation/tcc,fstudio/tinycc,acook/tinycc,run4flat/tinycc,andreiw/tinycc,FriedBreakfast/tcc,yousong/tinycc,rchandramouli/tinycc,mirror/tinycc,FriedBreakfast/tcc,gfwilliams/tinycc,gfwilliams/tinycc,seyko2/tinycc,andreiw/tinycc,run4flat/tinycc,fstudio/tinycc,acook/tinycc,fstudio/tinycc,Saectar/inherpreter,melkior/tinycc,metaeducation/tcc,leeduhem/tinycc