Extend -Wdynamic-class-memaccess to records containing dynamic classes

Reviewers: rtrieu

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4325

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211972 91177308-0d34-0410-b5e6-96231b3b80d8