ControlFlowBuilder.getExitPoint() now can return null if nothing was found #KT-10823 Fixed

Also #EA-73355 Fixed

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt10823.kt

@@ -0,0 +1,33 @@
+fun find2(): Any? {
+    fun visit(element: Any) {
+        <!RETURN_NOT_ALLOWED!>return@find2 element<!>
+    }
+    return null
+}
+
+// For find(): AssertionError at ControlFlowInstructionsGeneratorWorker.getExitPoint()
+
+fun find(): Any? {
+    object : Any() {
+        fun visit(element: Any) {
+            <!RETURN_NOT_ALLOWED!>return@find element<!>
+        }
+    }
+    return null
+}
+
+fun find4(): Any? {
+    <!NOT_YET_SUPPORTED_IN_INLINE!>inline fun visit(element: Any) {
+        <!RETURN_NOT_ALLOWED!>return@find4 element<!>
+    }<!>
+    return null
+}
+
+fun find3(): Any? {
+    object : Any() {
+        <!NOTHING_TO_INLINE!>inline<!> fun visit(element: Any) {
+            <!RETURN_NOT_ALLOWED!>return@find3 element<!>
+        }
+    }
+    return null
+}

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt10823.txt

@@ -0,0 +1,6 @@
+package
+
+public fun find(): kotlin.Any?
+public fun find2(): kotlin.Any?
+public fun find3(): kotlin.Any?
+public fun find4(): kotlin.Any?