[JS IR BE] Fix unbound symbols after deserialization

* restore broken psi2ir invariant

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

@@ -138,7 +138,7 @@ fun compile(
     val psi2IrContext = psi2IrTranslator.createGeneratorContext(moduleDescriptor, analysisResult.bindingContext, symbolTable)
     val irBuiltIns = psi2IrContext.irBuiltIns
 
-    var deserializer = JsIrLinker(moduleDescriptor, logggg, irBuiltIns, symbolTable)
+    val deserializer = JsIrLinker(moduleDescriptor, logggg, irBuiltIns, symbolTable)
 
     val deserializedModuleFragments = sortedImmediateDependencies.map {
         val moduleFile = File(it.klibPath, moduleHeaderFileName)

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/serialization/ir/JsIrLinker.kt

@@ -10,8 +10,6 @@ import org.jetbrains.kotlin.backend.common.library.CombinedIrFileReader
 import org.jetbrains.kotlin.backend.common.library.DeclarationId
 import org.jetbrains.kotlin.backend.common.serialization.*
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
-import org.jetbrains.kotlin.backend.common.serialization.knownBuiltins
-import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.symbols.IrClassifierSymbol
@@ -49,4 +47,17 @@ class JsIrLinker(
         moduleToReaderMap[moduleDescriptor] = CombinedIrFileReader(irFile)
         return deserializeIrModuleHeader(moduleDescriptor, byteArray, deserializationStrategy)
     }
+
+    override fun declareForwardDeclarations() {
+        // since for `knownBuiltIns` such as FunctionN it is possible to have unbound symbols after deserialization
+        // reference them through out lazy symbol table
+        with(symbolTable) {
+            ArrayList(unboundClasses).forEach { lazyWrapper.referenceClass(it.descriptor) }
+            ArrayList(unboundConstructors).forEach { lazyWrapper.referenceConstructor(it.descriptor) }
+            ArrayList(unboundEnumEntries).forEach { lazyWrapper.referenceEnumEntry(it.descriptor) }
+            ArrayList(unboundFields).forEach { lazyWrapper.referenceField(it.descriptor) }
+            ArrayList(unboundSimpleFunctions).forEach { lazyWrapper.referenceSimpleFunction(it.descriptor) }
+            ArrayList(unboundTypeParameters).forEach { lazyWrapper.referenceTypeParameter(it.descriptor) }
+        }
+    }
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/ExternalDependenciesGenerator.kt

@@ -60,8 +60,6 @@ class ExternalDependenciesGenerator(
 
         deserializer?.declareForwardDeclarations()
 
-        if (deserializer != null) return
-
         assertEmpty(symbolTable.unboundClasses, "classes")
         assertEmpty(symbolTable.unboundConstructors, "constructors")
         assertEmpty(symbolTable.unboundEnumEntries, "enum entries")