FIR CFG: merge data flow if called-in-place lambda may not be called

compiler/testData/codegen/box/smartCasts/kt44814.dot

@@ -713,8 +713,7 @@ digraph kt44814_kt {
     188 -> {189};
     189 -> {190};
     190 -> {191};
-    191 -> {239};
-    191 -> {192} [color=red];
+    191 -> {192 239};
     191 -> {239} [style=dashed];
     192 -> {193};
     193 -> {194};
@@ -776,7 +775,7 @@ digraph kt44814_kt {
     246 -> {247};
     247 -> {248};
     248 -> {249};
-    249 -> {192} [color=green];
+    249 -> {192};
     249 -> {239} [color=green style=dashed];
 
     subgraph cluster_68 {