Fix PR8767, improve diagnostic wording when allocating an object of an
abstract class type.

Patch by Stephen Hines, with a wording tweak from Doug applied by me.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125996 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed