Fix raw address breakpoints not resolving

Summary: An address breakpoint of the form "b 0x1000" won't resolve if it's created while the process isn't running. This patch deletes Address::SectionWasDeleted, renames Address::SectionWasDeletedPrivate to SectionWasDeleted (and makes it public), and changes the section check in Breakpoint::ModulesChanged back to its original form

Reviewers: jingham, #lldb

Reviewed By: jingham

Subscribers: davide, lldb-commits

Differential Revision: https://reviews.llvm.org/D51816

llvm-svn: 341849