[FIR, by demiurg] Fix exception in DFA for a case with lambda empty body

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/FirControlFlowGraphReferenceImpl.kt

@@ -19,4 +19,7 @@ class FirControlFlowGraphReferenceImpl(val controlFlowGraph: ControlFlowGraph) :
     override fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirControlFlowGraphReference {
         return this
     }
-}
+}
+
+val FirControlFlowGraphReference.controlFlowGraph: ControlFlowGraph?
+    get() = (this as? FirControlFlowGraphReferenceImpl)?.controlFlowGraph

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphBuilder.kt

@@ -173,7 +173,9 @@ class ControlFlowGraphBuilder {
             is StubNode -> firstPreviousNode.extractArgument()
             else -> fir.extractArgument()
         }
-        return exitsOfAnonymousFunctions.getValue(function).previousNodes.mapNotNull {
+
+        val exitNode = function.controlFlowGraphReference.controlFlowGraph?.exitNode ?: exitsOfAnonymousFunctions.getValue(function)
+        return exitNode.previousNodes.mapNotNull {
             it.extractArgument() as FirStatement?
         }
     }