Fix diagnostic test data to be consistent with FIR test data

compiler/testData/diagnostics/tests/functionLiterals/lambdaInLambda2.fir.kt

@@ -1,28 +0,0 @@
-// !DIAGNOSTICS: -UNUSED_VARIABLE
-
-// FILE: Function.java
-
-public interface Function<Param, Result> {
-    Result fun(Param param);
-}
-
-// FILE: AdapterProcessor.java
-
-public class AdapterProcessor<T, S> {
-    public AdapterProcessor(Function<? super T, ? extends S> conversion) {}
-}
-
-
-// FILE: main.kt
-
-interface PsiMethod {
-    val containingClass: PsiClass?
-}
-
-interface PsiClass
-
-fun test() {
-    val processor = AdapterProcessor<PsiMethod, PsiClass>(
-        Function { method: PsiMethod? -> method?.containingClass }
-    )
-}

compiler/testData/diagnostics/tests/functionLiterals/lambdaInLambda2.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_VARIABLE
 
 // FILE: Function.java