Fix false-positive for unnecessary-ellipsis checker on comparisons (#6075)

Closes #6071.

Co-authored-by: Pierre Sassoulas <[email protected]>

Author: skshetry

tests/functional/u/unnecessary/unnecessary_ellipsis.py

@@ -114,3 +114,18 @@ def func_with_ellipsis_default_arg(a = ...) -> None:
 
 # Ignore if the ellipsis is used with a lambda expression
 print("x", lambda: ...)
+
+
+def func1(val1, _):
+    if val1 is not ...:
+        pass
+
+
+def func2(val1, val2):
+    """Ignore if ellipsis is used on comparisons.
+    See https://github.com/PyCQA/pylint/issues/6071."""
+    if val1 is not ... and val2:
+        pass
+
+
+assert "x" != ...