Merge pull request #34367 from texasmichelle/remove-iso646

Adds an empty `_Differentiation` module

Author: texasmichelle

lib/SIL/IR/SILModule.cpp

@@ -32,6 +32,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/YAMLTraits.h"
 #include <functional>
+
 using namespace swift;
 using namespace Lowering;
 

stdlib/public/Differentiation/Empty.swift

@@ -1,3 +1,4 @@
 // SWIFT_ENABLE_TENSORFLOW
 // Empty Swift file, only for tensorflow branch.
 // See explanation in stdlib/public/Differentiation/CMakeLists.txt.
+public struct _Differentiation { }