ObjectiveC. 1) Warn when @dynamic (as well as synthesize)

property has the naming convention that implies 'ownership'.
2) improve on diagnostic and make it property specific.
3) fix the line number in the case of default property
synthesis. // rdar://15757510


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198905 91177308-0d34-0410-b5e6-96231b3b80d8