i#989: Treat fallthroughs as transfers in check_new_page_contig()
i#989: Treat fallthroughs as transfers in check_new_page_contig()

This prevents building bbs that fall through from a readonly vmarea into
a sandboxed area, as well as other incompatible area transitions.  If
the first instr of the bb is straddling a vmarea, we let bb building
continue with the new vmarea flags so we don't create an empty bb.  This
case is covered by the selfmod_last_byte() test.

Fixes issue 989.

Review URL: https://codereview.appspot.com/6843126

SVN-Revision: 1751

daksunt/dynamorio,sigma-random/dynamorio,daksunt/dynamorio,sigma-random/dynamorio,AmesianX/dynamorio,code4bones/dynamorio,code4bones/dynamorio,bl4ckic3/dynamorio,bl4ckic3/dynamorio,bl4ckic3/dynamorio,AmesianX/dynamorio,sigma-random/dynamorio,daksunt/dynamorio,daksunt/dynamorio,AmesianX/dynamorio,sigma-random/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,daksunt/dynamorio,code4bones/dynamorio,sigma-random/dynamorio,bl4ckic3/dynamorio,code4bones/dynamorio,bl4ckic3/dynamorio,AmesianX/dynamorio