+= tests fix

libraries/stdlib/test/collections/CollectionTest.kt

@@ -199,7 +199,7 @@ class CollectionTest {
         assertEquals(arrayListOf("foo", "bar", "cheese"), list2)
 
         // lets use a mutable variable
-        var list3 = arrayListOf("a", "b")
+        var list3 = listOf("a", "b")
         list3 += "c"
         assertEquals(arrayListOf("a", "b", "c"), list3)
     }
@@ -216,7 +216,7 @@ class CollectionTest {
         assertEquals(arrayListOf("foo", "bar", "cheese", "wine"), list)
 
         // lets use a mutable variable
-        var ml = a
+        var ml: List<String> = a
         ml += "beer"
         ml += b
         ml += "z"

libraries/stdlib/test/collections/ListSpecificTest.kt

@@ -44,7 +44,7 @@ class ListSpecificTest {
     Test fun mutableList() {
         val items = listOf("beverage", "location", "name")
 
-        var list = arrayListOf<String>()
+        var list = listOf<String>()
         for (item in items) {
             list += item
         }

libraries/stdlib/test/dom/DomTest.kt

@@ -23,7 +23,7 @@ class DomTest {
         e.setAttribute("class", "bar")
         assertCssClass(e, "bar")
 
-        doc += e
+        doc + e
         println("document ${doc.toXmlString()}")
     }