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

idea/testData/intentions/loopToCallChain/count/countSomethingAndNotNull.kt.after

@@ -0,0 +1,7 @@
+// WITH_RUNTIME
+// INTENTION_TEXT: "Replace with 'count{}'"
+// IS_APPLICABLE_2: false
+fun f(list: List<Any?>): Int{
+    val <caret>c = list.count { it != "" && it != null && it !is Int }
+    return c
+}