PY-15347 Optimize imports only after moved element was deleted from original file

Also I updated test data for existing test where because of sorting of
imports new from-import was added *after* existing star-import (and thus
star-import was indeed optimized out). As result that test didn't
manage to detect the new problem.

python/testData/refactoring/move/starImportWithUsages/before/src/a.py

@@ -1,3 +1,3 @@
-from b import *
+from zzz import *
 
 print(f())