[analyzer] Cast the result of a placement new-expression to the correct type.

This is necessary because further analysis will assume that the SVal's
type matches the AST type. This caused a crash when trying to perform
a derived-to-base cast on a C++ object that had been new'd to be another
object type.

Yet another crash in PR13763.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163442 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed