Do not output empty non-root packages in tests with txt

Mostly to avoid listing every internal package in
kotlin-stdlib/kotlin-reflect, as in
https://github.com/JetBrains/kotlin/blob/acd5b62148d797ffd24c4811d1d663f0c1ae7885/compiler/testData/diagnostics/testsWithUnsignedTypes/conversions/conversionOfSignedToUnsigned.txt#L144

compiler/testData/diagnostics/tests/generics/PseudoRawTypes.txt

@@ -2,48 +2,6 @@ package
 
 package java {
 
-    package java.awt {
-
-        package java.awt.event {
-        }
-    }
-
-    package java.beans {
-
-        package java.beans.beancontext {
-        }
-    }
-
-    package java.io {
-    }
-
-    package java.lang {
-
-        package java.lang.annotation {
-        }
-
-        package java.lang.reflect {
-        }
-    }
-
-    package java.net {
-    }
-
-    package java.nio {
-
-        package java.nio.charset {
-        }
-    }
-
-    package java.rmi {
-    }
-
-    package java.security {
-    }
-
-    package java.sql {
-    }
-
     package java.util {
 
         public open class Collection {
@@ -53,18 +11,6 @@ package java {
             public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
             public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         }
-
-        package java.util.concurrent {
-
-            package java.util.concurrent.atomic {
-            }
-
-            package java.util.concurrent.locks {
-            }
-        }
-
-        package java.util.regex {
-        }
     }
 }