Simplify creation of a bunch of ArrayRefs by using None, makeArrayRef or just letting them be implicitly created.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216525 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/StringRef.cpp

@@ -105,8 +105,8 @@ unsigned StringRef::edit_distance(llvm::StringRef Other,
                                   bool AllowReplacements,
                                   unsigned MaxEditDistance) const {
   return llvm::ComputeEditDistance(
-      llvm::ArrayRef<char>(data(), size()),
-      llvm::ArrayRef<char>(Other.data(), Other.size()),
+      makeArrayRef(data(), size()),
+      makeArrayRef(Other.data(), Other.size()),
       AllowReplacements, MaxEditDistance);
 }