JC IR IC: correct signatures for function types created during lowerings

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt

@@ -243,6 +243,14 @@ class JsIrBackendContext(
 
             override val functionAdapter: IrClassSymbol
                 get() = TODO("Not implemented")
+
+            override fun functionN(n: Int): IrClassSymbol {
+                return irFactory.stageController.withInitialIr { super.functionN(n) }
+            }
+
+            override fun suspendFunctionN(n: Int): IrClassSymbol {
+                return irFactory.stageController.withInitialIr { super.suspendFunctionN(n) }
+            }
         }
 
         override fun unfoldInlineClassType(irType: IrType): IrType? {

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/WholeWorldStageController.kt

@@ -44,10 +44,13 @@ class WholeWorldStageController : StageController() {
     override fun <T> withStage(stage: Int, fn: () -> T): T {
         val oldStage = currentStage
         currentStage = stage
+        val oldCurrentDeclaration = currentDeclaration
+        currentDeclaration = null
         return try {
             fn()
         } finally {
             currentStage = oldStage
+            currentDeclaration = oldCurrentDeclaration
         }
     }