Fix elf core file VMA-contiguous region collapsing.
Fix elf core file VMA-contiguous region collapsing.

Elf core files were collapsing core segments when the virtual memory
addresses were contiguous without checking if the core-file-backed
memory region was the same size as the segment's VMA region. Without
this extra check, any time regions were collapsed but the core-backed
region was smaller (and thus had a zero-filled hole at the end), the
collapse operation would break VMA to core file lookups for subsequent
collapsed regions.

This change fixes the following bug:
http://llvm.org/bugs/show_bug.cgi?id=18769



git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@201214 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb