sum and sumBy supported

idea/testData/intentions/loopToCallChain/sum/sumByIntsIntoLong.kt

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+// INTENTION_TEXT: "Replace with 'map{}.sum()'"
+// INTENTION_TEXT_2: "Replace with 'asSequence().map{}.sum()'"
+fun foo(list: List<Int>): Long {
+    var s = 0L
+    <caret>for (item in list) {
+        s += item
+    }
+    return s
+}