MS ABI: Mangle alias templates used as template-template arguments

A templated using declaration may be used as a template-template
argument.

Unfortunately, the VS "14" chooses '?' as the sole marker for the
argument.  This is problematic because it presupposes the possibility of
using more than one template-aliases as arguments to the same template.

This fixes PR20047.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214290 91177308-0d34-0410-b5e6-96231b3b80d8
Fix some cases of incorrect handling of lifetime extended temporaries.

MaterializeTemporaryExpr already contains information about the lifetime
of the temporary; if the lifetime is not the full statement, we do not
want to emit a destructor at the end of the full statement for it.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214292 91177308-0d34-0410-b5e6-96231b3b80d8
AST: Simplify some code

Iterator invalidation issues already force us to do one lookup and one
insert.
Don't use the particular bit-pattern of the 'Align' field to determine
whether or not we have already inserted into the TypeInfo DenseMap;
instead ask for an iterator to the TypeInfo entry.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214293 91177308-0d34-0410-b5e6-96231b3b80d8