[DWARFv5][DWARFLinker] Add stripped template names into .debug_names.

The D153869 patch stopped storing stripped template names into
.debug_names accelerator table. This patch restores original
behavior as lldb relies on presenting stripped names. Changes for
llvm-dwarfdump would be done as a separate patch.

Differential Revision: https://reviews.llvm.org/D155070