Use `tempfile.mkstemp` instead of `tempfile.mktemp`.

The `tempfile.mktemp` function is [deprecated](https://docs.python.org/3/library/tempfile.html#tempfile.mktemp) due to [security issues](https://cwe.mitre.org/data/definitions/377.html).

The switch is easy to do.

PiperOrigin-RevId: 420359224
Change-Id: I7bfc1df9cf931f45ec85d4878874ef41b9c55474
diff --git a/tensorflow/python/debug/cli/readline_ui_test.py b/tensorflow/python/debug/cli/readline_ui_test.py
index 4d3c3c3..fa37a64 100644
--- a/tensorflow/python/debug/cli/readline_ui_test.py
+++ b/tensorflow/python/debug/cli/readline_ui_test.py
@@ -31,9 +31,11 @@
   """Test subclass of ReadlineUI that bypasses terminal manipulations."""
 
   def __init__(self, on_ui_exit=None, command_sequence=None):
+    _, config_file_path = tempfile.mkstemp()  # safe to ignore fd
     readline_ui.ReadlineUI.__init__(
-        self, on_ui_exit=on_ui_exit,
-        config=cli_config.CLIConfig(config_file_path=tempfile.mktemp()))
+        self,
+        on_ui_exit=on_ui_exit,
+        config=cli_config.CLIConfig(config_file_path=config_file_path))
 
     self._command_sequence = command_sequence
     self._command_counter = 0
@@ -164,7 +166,7 @@
     self.assertTrue(observer["callback_invoked"])
 
   def testIncompleteRedirectWorks(self):
-    output_path = tempfile.mktemp()
+    _, output_path = tempfile.mkstemp()  # safe to ignore fd
 
     ui = MockReadlineUI(
         command_sequence=["babble -n 2 > %s" % output_path, "exit"])