Revert "[lldb] Fix string summary of an empty NSPathStore2"

This reverts commit 939ca455.

This failed on the debian bot for some reason:
  File "/home/worker/lldb-x86_64-debian/lldb-x86_64-debian/llvm-project/lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/TestDataFormatterStdString.py", line 67, in test_with_run_command
    "s summary wrong")
AssertionError: 'L"hello world! מזל טוב!\\0!\\0!!!!\\0\\0A\\0\\U0000fffd\\U0000fffd\\U0000fffd\\ [truncated]... != 'L"hello world! מזל טוב!"'
Diff is 2156 characters long. Set self.maxDiff to None to see it. : s summary wrong