[K/N][tests] Fix kt42208WithPassingLambdaToAnotherFunction.kt for K2

It seems that K2 doesn't support `UnitConversionsOnArbitraryExpressions`
experimental language feature (KT-56011), while the test accidentally
relied on it.

Improve the test code so that it doesn't need this language feature
anymore, and enable the test for K2.

^KT-65553 Fixed

native/native.tests/testData/lldb/kt42208WithPassingLambdaToAnotherFunction.kt

@@ -1,9 +1,5 @@
 // KIND: STANDALONE_LLDB
-// FREE_COMPILER_ARGS: -XXLanguage:+UnitConversionsOnArbitraryExpressions
-// IGNORE_BACKEND_K2: NATIVE
 // FIR_IDENTICAL
-// Not really `FIR_IDENTICAL`, because we ignore thois test for FIR, but with this directive presented we don't need to create separate `fir.txt` file for dump.
-
 // FILE: kt42208-1.kt
 fun main() {
     val a = foo()
@@ -17,6 +13,6 @@ inline fun foo() = { ->
     list.add(A())
 }
 // FILE: kt42208-3.kt
-fun bar(v:(()->Unit)) {
+fun bar(v:(()->Boolean)) {
     v()
 }