Remove TestFileLibTiff.test_save_many_compressed()

It is the slowest test of the suite, saving the same image
10 000 times to find leaking file descriptors.

It was added in March 2023, e953978, as a test for 2299490
that fixed a file descriptor leak.

The TIFF cleanup path was subsequently cleaned up in June 2023
(e45da2a) and October 2024 (7edf952) to avoid `os.dup()`
at all.

Author: akx

Tests/test_file_libtiff.py

@@ -1281,12 +1281,6 @@ def test_save_zero(self, compression: str | None, tmp_path: Path) -> None:
         with pytest.raises(ValueError, match="cannot write empty image"):
             im.save(out, compression=compression)
 
-    def test_save_many_compressed(self, tmp_path: Path) -> None:
-        im = hopper()
-        out = tmp_path / "temp.tif"
-        for _ in range(10000):
-            im.save(out, compression="jpeg")
-
     @pytest.mark.parametrize(
         "path, sizes",
         (