IR text tests: Stable blank lines between declarations in class

Rework rendering of kt-like dump and signatures dump in order to avoid
unstable blank line between declarations of the same level:
1. No blank line for the first declaration inside the member scope of
the class.
2. Always a single blank line between each two subsequent declarations
inside the member scope of the class.

compiler/testData/ir/irText/expressions/funInterface/arrayAsVarargAfterSamArgument_fi.sig.kt.txt

@@ -2,7 +2,6 @@
 //   Mangled name: IRunnable
 //   Public signature: /IRunnable|null[0]
 fun interface IRunnable {
-
   // CHECK:
   //   Mangled name: IRunnable#run(){}
   //   Public signature: /IRunnable.run|-991178076551934874[0]

compiler/testData/ir/irText/expressions/funInterface/basicFunInterfaceConversion.sig.kt.txt

@@ -2,7 +2,6 @@
 //   Mangled name: Foo
 //   Public signature: /Foo|null[0]
 fun interface Foo {
-
   // CHECK JVM_IR:
   //   Mangled name: Foo#invoke(){}kotlin.String
   //   Public signature: /Foo.invoke|8861605044563078664[0]

compiler/testData/ir/irText/expressions/funInterface/castFromAny.sig.kt.txt

@@ -2,7 +2,6 @@
 //   Mangled name: KRunnable
 //   Public signature: /KRunnable|null[0]
 fun interface KRunnable {
-
   // CHECK:
   //   Mangled name: KRunnable#invoke(){}
   //   Public signature: /KRunnable.invoke|-4663091332620260873[0]

compiler/testData/ir/irText/expressions/funInterface/functionSupertype.kt.txt

@@ -1,5 +1,4 @@
 fun interface Foo : Function0<Int> {
-
 }
 
 fun id(foo: Foo): Any {

compiler/testData/ir/irText/expressions/funInterface/functionSupertype.sig.kt.txt

@@ -2,7 +2,6 @@
 //   Mangled name: Foo
 //   Public signature: /Foo|null[0]
 fun interface Foo : Function0<Int> {
-
   // CHECK JVM_IR:
   //   Mangled name: Foo#invoke(){}kotlin.Int
   //   Public signature: /Foo.invoke|906964710558498066[0]

compiler/testData/ir/irText/expressions/funInterface/partialSam.sig.kt.txt

@@ -54,7 +54,6 @@ class J {
 //   Mangled name: Fn
 //   Public signature: /Fn|null[0]
 fun interface Fn<T : Any?, R : Any?> {
-
   // CHECK JVM_IR:
   //   Mangled name: Fn#run(kotlin.String;kotlin.Int;1:0){}1:1
   //   Public signature: /Fn.run|6229634511602909233[0]

compiler/testData/ir/irText/expressions/funInterface/samConversionInVarargs.sig.kt.txt

@@ -2,7 +2,6 @@
 //   Mangled name: IFoo
 //   Public signature: /IFoo|null[0]
 fun interface IFoo {
-
   // CHECK:
   //   Mangled name: IFoo#foo(kotlin.Int){}
   //   Public signature: /IFoo.foo|-104159190164110731[0]

compiler/testData/ir/irText/expressions/funInterface/samConversionInVarargsMixed.sig.kt.txt

@@ -2,7 +2,6 @@
 //   Mangled name: MyRunnable
 //   Public signature: /MyRunnable|null[0]
 fun interface MyRunnable {
-
   // CHECK:
   //   Mangled name: MyRunnable#run(){}
   //   Public signature: /MyRunnable.run|-991178076551934874[0]

compiler/testData/ir/irText/expressions/funInterface/samConversionOnCallableReference.sig.kt.txt

@@ -2,7 +2,6 @@
 //   Mangled name: KRunnable
 //   Public signature: /KRunnable|null[0]
 fun interface KRunnable {
-
   // CHECK:
   //   Mangled name: KRunnable#run(){}
   //   Public signature: /KRunnable.run|-991178076551934874[0]

compiler/testData/ir/irText/expressions/funInterface/samConversionsWithSmartCasts.fir.kt.txt

@@ -83,7 +83,6 @@ fun <T> test7b(a: T) where T : Function1<Int, Unit>, T : Function0<Unit> {
 }
 
 interface Unrelated {
-
 }
 
 fun <T> test7c(a: T) where T : Unrelated, T : Function0<Unit> {

compiler/testData/ir/irText/expressions/funInterface/samConversionsWithSmartCasts.kt.txt

@@ -83,7 +83,6 @@ fun <T> test7b(a: T) where T : Function1<Int, Unit>, T : Function0<Unit> {
 }
 
 interface Unrelated {
-
 }
 
 fun <T> test7c(a: T) where T : Unrelated, T : Function0<Unit> {

compiler/testData/ir/irText/expressions/funInterface/samConversionsWithSmartCasts.sig.kt.txt

@@ -2,7 +2,6 @@
 //   Mangled name: KRunnable
 //   Public signature: /KRunnable|null[0]
 fun interface KRunnable {
-
   // CHECK:
   //   Mangled name: KRunnable#run(){}
   //   Public signature: /KRunnable.run|-991178076551934874[0]
@@ -15,7 +14,6 @@ fun interface KRunnable {
 //   Mangled name: Unrelated
 //   Public signature: /Unrelated|null[0]
 interface Unrelated {
-
 }
 
 // CHECK JVM_IR: