message: [FileSpec] Simplify getting extension and stem.
  As noted by Pavel on lldb-commits, we don't need the temp path, we can
  just pass the filename directly into extension() and path().
diff: @@ -585,17 +585,12 @@ void FileSpec::GetPath(llvm::SmallVectorImpl<char> &path,
  }
  ConstString FileSpec::GetFileNameExtension() const {
  - llvm::SmallString<64> current_path;
  - current_path.append(m_filename.GetStringRef().begin(),
  - m_filename.GetStringRef().end());
  - return ConstString(llvm::sys::path::extension(current_path, m_style));
  + return ConstString(
  + llvm::sys::path::extension(m_filename.GetStringRef(), m_style));
  }
  ConstString FileSpec::GetFileNameStrippingExtension() const {
  - llvm::SmallString<64> current_path;
  - current_path.append(m_filename.GetStringRef().begin(),
  - m_filename.GetStringRef().end());
  - return ConstString(llvm::sys::path::stem(current_path, m_style));
  + return ConstString(llvm::sys::path::stem(m_filename.GetStringRef(), m_style));
  }
  //------------------------------------------------------------------
  