Add test for outdated smart cast with elvis issue

#KT-5335 Obsolete

compiler/testData/diagnostics/tests/smartCasts/elvisNothingRHS.txt

@@ -0,0 +1,11 @@
+package
+
+internal fun test(/*0*/ a: C?, /*1*/ nn: () -> kotlin.Nothing?): kotlin.Unit
+
+internal final class C {
+    public constructor C()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    internal final fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}