count() to merge with filterNotNull and filterIsInstance + changed test for KT-14191 to use sum()

idea/testData/intentions/loopToCallChain/KT14191.kt

@@ -0,0 +1,12 @@
+// WITH_RUNTIME
+// INTENTION_TEXT: "Replace with 'filterNotNull().sum()'"
+// INTENTION_TEXT_2: "Replace with 'asSequence().filterNotNull().sum()'"
+fun f(list: List<Int?>): Int{
+    var r = 0
+    <caret>for (d in list) {
+        if (d != null) {
+            r += d
+        }
+    }
+    return r
+}