[tests] use Q15169668 item for wikibase_tests.py

wikibase_tests.TestLoadRevisionsCaching needs up to 3 minutes to be
finished with Q60 (New York City). Replace it with Q15169668 (Pywikibot)
thich needs less than a tenth of this time.

Bug: T334809
Change-Id: Ib9a2dcc83e60696a616df8bf81653453d566176f
---
M tests/wikibase_tests.py
1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/tests/wikibase_tests.py b/tests/wikibase_tests.py
index 435ce88..ea322ed 100755
--- a/tests/wikibase_tests.py
+++ b/tests/wikibase_tests.py
@@ -64,7 +64,7 @@
 
     def setUp(self):
         """Setup test."""
-        self._page = ItemPage(self.get_repo(), 'Q60')
+        self._page = ItemPage(self.get_repo(), 'Q15169668')
         super().setUp()
 
     def test_page_text(self):

