Add a convenient way to query whether a type is POD.

This also has the pleasant side-effect of allowing the
TypeInfo for tuples/etc to not be unnecessarily built.

Swift SVN r3475

lib/IRGen/IRGenModule.h

@@ -160,6 +160,7 @@ public:
   llvm::PointerType *isSingleIndirectValue(CanType T, ExplosionKind kind);
   llvm::PointerType *requiresIndirectResult(CanType T, ExplosionKind kind);
   bool hasTrivialMetatype(CanType type);
+  bool isPOD(CanType type, ResilienceScope scope);
 
   bool isResilient(Decl *decl) { return false; }