Extraction refactorings: Do not suggest extraction of type elements

#KT-3994 Fixed

idea/src/org/jetbrains/jet/plugin/refactoring/JetRefactoringUtil.java

@@ -432,6 +432,9 @@ public class JetRefactoringUtil {
                     }
                 }
             }
+            else if (element instanceof JetTypeElement) {
+                expressions.clear();
+            }
             element = element.getParent();
         }
         return expressions;

idea/testData/refactoring/introduceVariable/TypeElement.kt

@@ -0,0 +1,3 @@
+fun foo(t: Any) {
+    val x = t as <caret>List<String>
+}

idea/testData/refactoring/introduceVariable/TypeElement.kt.after

@@ -0,0 +1,4 @@
+fun foo(t: Any) {
+    val list = t as List<String>
+    val x = list
+}

idea/tests/org/jetbrains/jet/plugin/refactoring/introduce/introduceVariable/JetExtractionTestGenerated.java

@@ -243,6 +243,12 @@ public class JetExtractionTestGenerated extends AbstractJetExtractionTest {
             doIntroduceVariableTest(fileName);
         }
 
+        @TestMetadata("TypeElement.kt")
+        public void testTypeElement() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/TypeElement.kt");
+            doIntroduceVariableTest(fileName);
+        }
+
         @TestMetadata("UnresolvedOccurrences.kt")
         public void testUnresolvedOccurrences() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/refactoring/introduceVariable/UnresolvedOccurrences.kt");