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/imports/CheckJavaVisibility.txt

@@ -47,6 +47,3 @@ package j {
         public open fun javaM(): kotlin.Unit
     }
 }
-
-package k {
-}

compiler/testData/diagnostics/tests/imports/CheckVisibility.txt

@@ -39,18 +39,7 @@ package k {
     }
 }
 
-package k2 {
-}
-
 
 // -- Module: <m2> --
 package
 
-package k {
-}
-
-package k2 {
-}
-
-package k3 {
-}

compiler/testData/diagnostics/tests/imports/ClassClash.txt

@@ -33,9 +33,6 @@ package
 
 public fun test(/*0*/ b: a.B): kotlin.Unit
 
-package a {
-}
-
 
 // -- Module: <top_m1> --
 package

compiler/testData/diagnostics/tests/imports/ClassClashStarImport.txt

@@ -33,9 +33,6 @@ package
 
 public fun test(/*0*/ b: a.B): kotlin.Unit
 
-package a {
-}
-
 
 // -- Module: <top_m1> --
 package

compiler/testData/diagnostics/tests/imports/ClassImportsConflicting.txt

@@ -1,8 +1,5 @@
 package
 
-package a {
-}
-
 package b {
 
     public object O {

compiler/testData/diagnostics/tests/imports/ImportsConflicting.txt

@@ -1,8 +1,5 @@
 package
 
-package a {
-}
-
 package b {
     public fun foo(): kotlin.Int
 }

compiler/testData/diagnostics/tests/imports/MalformedImports.txt

@@ -1,4 +1,2 @@
 package
 
-package test {
-}

compiler/testData/diagnostics/tests/imports/PackageVsClass.txt

@@ -58,9 +58,6 @@ public fun test2(/*0*/ ab_c: a.b.c): kotlin.Unit
 package a {
     public fun test(/*0*/ a_b: a.b): kotlin.Unit
     public fun test2(/*0*/ ab_c: a.b.c): kotlin.Unit
-
-    package a.b {
-    }
 }
 
 
@@ -73,7 +70,4 @@ public fun test2(/*0*/ ab_c: a.b.c): kotlin.Unit
 package a {
     public fun test(/*0*/ a_b: a.b): kotlin.Unit
     public fun test2(/*0*/ ab_c: a.b.c): kotlin.Unit
-
-    package a.b {
-    }
 }

compiler/testData/diagnostics/tests/imports/TopLevelClassVsPackage.txt

@@ -50,6 +50,3 @@ package
 public fun test(/*0*/ a_b: a.b): kotlin.Unit
 public fun test2(/*0*/ _a: a): kotlin.Unit
 public fun test3(/*0*/ _a: a): kotlin.Unit
-
-package a {
-}

compiler/testData/diagnostics/tests/imports/WrongImport.txt

@@ -44,7 +44,4 @@ package a {
             public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         }
     }
-
-    package a.b {
-    }
 }