nixos/systemd-boot-builder: cache boot_path()

It calls Path.resolve() and is invoked several times per generation for
the same store paths.

nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py

@@ -3,6 +3,7 @@ import argparse
 import ctypes
 import datetime
 import errno
+import functools
 import hashlib
 import os
 import re
@@ -330,6 +331,7 @@ def bootspec_from_json(bootspec_json: dict[str, Any]) -> BootSpec:
     )
 
 
+@functools.lru_cache(maxsize=None)
 def boot_path(file: Path) -> Path:
     store_file_path = file.resolve()
     suffix = store_file_path.name