extract method: exclude return statements without value from occurrence analyzing; do not suggest artificial return type if return statements break control flow

java/java-tests/testData/refactoring/extractMethod/NoReturnTypesSuggested.java

@@ -0,0 +1,7 @@
+class X {
+  void foo() {
+      <selection>if (true) return;
+      System.out.println();
+      </selection>
+  }
+}

java/java-tests/testData/refactoring/extractMethod/NoReturnTypesSuggested_after.java

@@ -0,0 +1,11 @@
+class X {
+  void foo() {
+      newMethod();
+      
+  }
+
+    private int newMethod() {
+        if (true) return;
+        System.out.println();
+    }
+}