[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/multifile/importFromObject.fir.txt

@@ -1,4 +1,6 @@
 FILE: a.kt
+    package a
+
     public final object A : R|kotlin/Any| {
         private constructor(): R|a/A| {
             super<R|kotlin/Any|>()
@@ -9,6 +11,8 @@ FILE: a.kt
 
     }
 FILE: b.kt
+    package b
+
     public final fun bar(): R|kotlin/Unit| {
         Q|a/A|.R|a/A.foo|()
     }