[JS IR BE] Fix fqNames in moveBodilessDeclarationsToSeparatePlace

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

@@ -575,4 +575,13 @@ val IrDeclaration.file: IrFile get() = parent.let {
         is IrDeclaration -> it.file
         else -> TODO("Unexpected declaration parent")
     }
-}
+}
+
+fun IrDeclarationWithName.getFqName(): FqName? {
+    val parentFqName = when (val parent = parent) {
+        is IrPackageFragment -> parent.fqName
+        is IrDeclarationWithName -> parent.getFqName()
+        else -> null
+    }
+    return parentFqName?.child(name)
+}