testsuite: only use follow_symlinks if supported

On Windows, follow_symlinks is not supported by every os function yet, using False can raise a NotImplementedError.
Check os.supports_follow_symlinks to decide whether to use True or False.

Author: RayyanAnsari

src/borg/testsuite/__init__.py

@@ -147,8 +147,8 @@ def is_utime_fully_supported():
         else:
             open(filepath, "w").close()
         try:
-            os.utime(filepath, (1000, 2000), follow_symlinks=False)
-            new_stats = os.stat(filepath, follow_symlinks=False)
+            os.utime(filepath, (1000, 2000), follow_symlinks=False if os.utime in os.supports_follow_symlinks else True)
+            new_stats = os.stat(filepath, follow_symlinks=False if os.stat in os.supports_follow_symlinks else True)
             if new_stats.st_atime == 1000 and new_stats.st_mtime == 2000:
                 return True
         except OSError: