Simplify code with the in place path::native. No functionality change.

llvm-svn: 190515
diff --git a/clang/lib/Tooling/Tooling.cpp b/clang/lib/Tooling/Tooling.cpp
index 6f7e7b6..b420ba9 100644
--- a/clang/lib/Tooling/Tooling.cpp
+++ b/clang/lib/Tooling/Tooling.cpp
@@ -134,9 +134,8 @@
   llvm::error_code EC = llvm::sys::fs::make_absolute(AbsolutePath);
   assert(!EC);
   (void)EC;
-  SmallString<1024> PathStorage;
-  llvm::sys::path::native(Twine(AbsolutePath), PathStorage);
-  return PathStorage.str();
+  llvm::sys::path::native(AbsolutePath);
+  return AbsolutePath.str();
 }
 
 ToolInvocation::ToolInvocation(