PY-21292 Properly delete obsolete imports of moved symbols

Some of them might have been left if the corresponding symbols were used
and imported via "from" imports in the same module or new imports of them
were combined with some exiting "from" imports in a dependent module.

python/testSrc/com/jetbrains/python/refactoring/PyMoveTest.java

@@ -361,6 +361,16 @@ public class PyMoveTest extends PyTestCase {
     doMoveSymbolTest("func", "b.py");
   }
 
+  // PY-21292
+  public void testStaleFromImportsRemovedWhenSeveralMovedSymbolsUsedInSameModule() {
+    doMoveSymbolsTest("b.py", "A", "B");
+  }
+
+  // PY-21292
+  public void testStaleFromImportRemovedWhenNewImportCombinedWithExistingImport() {
+    doMoveSymbolTest("A", "b.py");
+  }
+
   private void doMoveFileTest(String fileName, String toDirName) {
     Project project = myFixture.getProject();
     PsiManager manager = PsiManager.getInstance(project);