Make test_shot_view_ref_count refcount check work on Python 3.14

Summary:
On Python 3.14, `sys.getrefcount` on a local variable returns one less than on 3.12 (the interpreter borrows local references for the call), so the absolute `== 2` check fails. Comparing against a plain local keeps the "nothing else holds the reconstruction" check on both versions.

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Differential Revision: D122956965

fbshipit-source-id: 399b777013c49a93a8fd5735779a70e4b06eac71

Author: itamaro

opensfm/test/test_types.py

@@ -267,9 +267,12 @@ def test_shot_view_ref_count() -> None:
     rec.create_shot("shot1", "camera1", pygeometry.Pose())
     rec.create_shot("shot2", "camera1", pygeometry.Pose())
 
-    # The reconstruction has ref count = 2
+    # Only the local variable references the reconstruction. Compare against
+    # another local: Python 3.14 borrows local references when calling
+    # getrefcount, so the absolute value differs between versions.
+    local_only = object()
     count = sys.getrefcount(rec)
-    assert count == 2
+    assert count == sys.getrefcount(local_only)
 
     # The map has a bigger ref count because all the views are referencing it
     count = sys.getrefcount(rec.map)