auto cast widget to its original type

- change property return type signatures from View to actual widget type
- simplify and update tests

compiler/testData/android/converter/singleFile/layout.kt

@@ -1,21 +1,16 @@
 import android.app.Activity
 import android.view.View
+import android.widget.*
 
-val Activity.item_detail_container: View
-    get() = findViewById(R.id.item_detail_container)!!
+val Activity.item_detail_container: FrameLayout
+    get() = findViewById(R.id.item_detail_container) as FrameLayout
 
-val Activity.textView1: View
-    get() = findViewById(R.id.textView1)!!
+val Activity.textView1: TextView
+    get() = findViewById(R.id.textView1) as TextView
 
-val Activity.password: View
-    get() = findViewById(R.id.password)!!
+val Activity.password: EditText
+    get() = findViewById(R.id.password) as EditText
 
-val Activity.textView2: View
-    get() = findViewById(R.id.textView2)!!
-
-val Activity.passwordConfirmation: View
-    get() = findViewById(R.id.passwordConfirmation)!!
-
-val Activity.login: View
-    get() = findViewById(R.id.login)!!
+val Activity.login: Button
+    get() = findViewById(R.id.login) as Button
 

compiler/testData/android/converter/singleFile/layout.xml

@@ -18,22 +18,6 @@
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:ems="10"
-        android:inputType="textPassword" >
-
-      <requestFocus />
-    </EditText>
-
-    <TextView
-        android:id="@+id/textView2"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:text="Repeat your password" />
-
-    <EditText
-        android:id="@+id/passwordConfirmation"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:ems="10"
         android:inputType="textPassword" />
 
     <Button

compiler/testData/android/fakeHelpers/Widgets.kt

@@ -0,0 +1,6 @@
+package android.widget
+
+class EditText
+class TextView
+class Button
+class FrameLayout