[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/smartCasts/safecalls/falseSecondArgument.fir.kt

@@ -0,0 +1,7 @@
+// !WITH_NEW_INFERENCE
+
+fun calc(x: List<String>?, y: Int?): Int {
+    x?.subList(y!! - 1, y)
+    // y!! above should not provide smart cast here
+    return y
+}