use mockJdk18 by default in LightCodeInsightTestCase; remove dependency on swing/net classes in some tests

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/createClassFromNew/after8.java

@@ -1,12 +1,14 @@
 // "Create class 'MyTableModel'" "true"
-import javax.swing.*;
-import javax.swing.table.TableModel;
 
 public class Test {
     public static void main() {
         JTable table = new JTable(new MyTableModel());
     }
 }
+class JTable {
+  JTable(TableModel t) {}
+}
+interface TableModel {}
 
 <caret>public class MyTableModel implements TableModel {
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/createClassFromNew/before8.java

@@ -1,8 +1,11 @@
 // "Create class 'MyTableModel'" "true"
-import javax.swing.*;
 
 public class Test {
     public static void main() {
         JTable table = new JTable(new MyTable<caret>Model());
     }
-}
+}
+class JTable {
+  JTable(TableModel t) {}
+}
+interface TableModel {}