The issue this solves is that buffer_internal_preload() is only called when
STATE_VDECL or STATE_STREAMSRC is invalidated, but that doesn't happen for
regular buffer maps. We'd like to be able to just call
buffer_internal_preload() here, but buffer_internal_preload() has dependencies
on context_stream_info_from_declaration() and vice versa.

tools: Only allow the absolute difference in bracket pairs to be less than 128, since we need the sign.