Implement equals/hashcode for IrDeclarationOrigin so deserialized unknown origins would be compared correctly

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrDeclarationOrigin.kt

@@ -55,4 +55,18 @@ abstract class IrDeclarationOriginImpl(
     override val isSynthetic: Boolean = false
 ) : IrDeclarationOrigin {
     override fun toString(): String = name
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is IrDeclarationOriginImpl) return false
+
+        if (name != other.name) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        return name.hashCode()
+    }
+
 }

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/IrModuleDeserializer.kt

@@ -1153,7 +1153,11 @@ abstract class IrModuleDeserializer(
     private val allKnownOrigins =
         IrDeclarationOrigin::class.nestedClasses.toList() + DeclarationFactory.FIELD_FOR_OUTER_THIS::class
     val originIndex = allKnownOrigins.map { it.objectInstance as IrDeclarationOriginImpl }.associateBy { it.name }
-    fun deserializeIrDeclarationOrigin(proto: KotlinIr.IrDeclarationOrigin) = originIndex[deserializeString(proto.custom)]!!
+
+    fun deserializeIrDeclarationOrigin(proto: KotlinIr.IrDeclarationOrigin): IrDeclarationOriginImpl {
+        val originName = deserializeString(proto.custom)
+        return originIndex[originName] ?: object : IrDeclarationOriginImpl(originName) {}
+    }
 
     open fun deserializeDeclaration(proto: KotlinIr.IrDeclaration, parent: IrDeclarationParent?): IrDeclaration {