Split or glue together checks for not null and is instance + more intelligent use of filter vs filterTo

#KT-14284 Fixed
 #KT-14286 Fixed
 #KT-14287 Fixed
 #KT-14303 Fixed

idea/testData/intentions/loopToCallChain/smartCasts/smartCastRequired2.kt.after

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+// INTENTION_TEXT: "Replace with '...filter{}.map{}.firstOrNull()'"
+// INTENTION_TEXT_2: "Replace with 'asSequence()...filter{}.map{}.firstOrNull()'"
+fun foo(list: List<Any>, o: Any): Int? {
+    return list
+            .filterIsInstance<String>()
+            .filter { it.length > 0 }
+            .map { it.length * 2 }
+            .firstOrNull()
+}