Add a test on skipping the comments before the source statement in Extract Method

python/testData/refactoring/extractmethod/CommentsPrecedingSourceStatement.after.py

@@ -0,0 +1,10 @@
+x = 42
+
+# print('commented')
+def func():
+    return x ** 2
+
+
+# comment 1
+# comment 2
+print(func())

python/testData/refactoring/extractmethod/CommentsPrecedingSourceStatement.before.py

@@ -0,0 +1,7 @@
+x = 42
+
+# print('commented')
+
+# comment 1
+# comment 2
+print(<selection>x ** 2</selection>)

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

@@ -286,4 +286,8 @@ public class PyExtractMethodTest extends LightMarkedTestCase {
   public void testAwaitExpression() {
     doTest("bar", LanguageLevel.PYTHON35);
   }
+
+  public void testCommentsPrecedingSourceStatement() {
+    doTest("func");
+  }
 }