[FIR] Include generated declarations into FIR dump in tests

Also include non root package directive of FirFile to dump

compiler/fir/analysis-tests/testData/resolve/defaultJavaImportHiding.fir.txt

@@ -1,4 +1,6 @@
 FILE: LinkedList.kt
+    package foo
+
     public final class LinkedList<T> : R|java/util/LinkedList<T>| {
         public constructor<T>(): R|foo/LinkedList<T>| {
             super<R|java/util/LinkedList<T>|>()
@@ -6,6 +8,8 @@ FILE: LinkedList.kt
 
     }
 FILE: HashSet.kt
+    package util
+
     public final class HashSet<T> : R|java/util/HashSet<T>| {
         public constructor<T>(): R|util/HashSet<T>| {
             super<R|java/util/HashSet<T>|>()
@@ -13,6 +17,8 @@ FILE: HashSet.kt
 
     }
 FILE: main.kt
+    package foo
+
     public final class LinkedHashMap<K, V> : R|java/util/LinkedHashMap<K, V>| {
         public constructor<K, V>(): R|foo/LinkedHashMap<K, V>| {
             super<R|java/util/LinkedHashMap<K, V>|>()