[ms-cxxabi] Fix the calling convention for operator new in records

Summary:
Operator new, new[], delete, and delete[] are all implicitly static when
declared inside a record.  CXXMethodDecl already knows this, but we need
to account for that before we pick the calling convention for the
function type.

Fixes PR17371.

Reviewers: rsmith

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1761

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192150 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/MicrosoftMangle.cpp b/lib/AST/MicrosoftMangle.cpp
index cd0063c..ab0db1a 100644
--- a/lib/AST/MicrosoftMangle.cpp
+++ b/lib/AST/MicrosoftMangle.cpp
@@ -316,9 +316,7 @@
 
   // We should never ever see a FunctionNoProtoType at this point.
   // We don't even know how to mangle their types anyway :).
-  TypeSourceInfo *TSI = FD->getTypeSourceInfo();
-  QualType T = TSI ? TSI->getType() : FD->getType();
-  const FunctionProtoType *FT = T->castAs<FunctionProtoType>();
+  const FunctionProtoType *FT = FD->getType()->castAs<FunctionProtoType>();
 
   // extern "C" functions can hold entities that must be mangled.
   // As it stands, these functions still need to get expressed in the full