Add test for outdated smart cast with elvis issue

#KT-5335 Obsolete

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

@@ -8,4 +8,4 @@ fun test(a: C?, nn: () -> Nothing?) {
 
     a ?: return
     <!DEBUG_INFO_SMARTCAST!>a<!>.foo()
-}
+}

compiler/testData/diagnostics/tests/smartCasts/elvisRHS.kt

@@ -0,0 +1,10 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+// KT-5335
+
+fun foo(p1: String?, p2: String?) {
+    if (p2 != null) {
+        val v = p1 ?: <!DEBUG_INFO_SMARTCAST!>p2<!>
+        val size = v.length
+    }
+}

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

@@ -0,0 +1,3 @@
+package
+
+internal fun foo(/*0*/ p1: kotlin.String?, /*1*/ p2: kotlin.String?): kotlin.Unit