We need refresh opened java files after changing Java Compile Preferences

[ddementieva]

Steps to reproduce:

1. Create new project from Spring sample.
2. Open project and wait until IDE resolves dependencies.
3. Open GreetingController class from created project.
4. Add code "int l = 0;" to the method "handleRequest";
   IDE should create warning marker for added code line.
5. Go to: Profile -> Preferences -> Java Compiler
6. Set value "error" for properties: "Value of local variable is not used": .
7. Click "Save" button.
   Actual result: In the opened editor still exist warning marker. It'll be changed only after reopen file.
   Expected result: editor should change warning marker to the error marker because java compiler preference was changed.