gh-145678: Remove unnecessary try/except in test

The iterator is never exhausted at this point, so StopIteration
cannot be raised.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sampsonc

Lib/test/test_itertools.py

@@ -767,10 +767,7 @@ def __init__(self, val, do_advance):
             def __eq__(self, other):
                 if self.do_advance:
                     self.do_advance = False
-                    try:
-                        next(g)
-                    except StopIteration:
-                        pass
+                    next(g)
                     return NotImplemented
                 return self.val == other.val