K1/K2: add a test confirming current behavior of KT-57014 case

compiler/testData/diagnostics/tests/samConversions/samConversionToGenericWrongNullability.kt

@@ -0,0 +1,13 @@
+// ISSUE: KT-57014
+// FULL_JDK
+// JVM_TARGET: 1.8
+
+import java.util.function.Supplier
+
+fun main() {
+    val sam = Supplier<String> {
+        foo()
+    }
+}
+
+fun foo(): String? = null