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

compiler/testData/diagnostics/tests/smartCasts/varnotnull/ifVarNotNullAnd.fir.kt

@@ -0,0 +1,13 @@
+// See KT-5737
+fun get(): String? {
+    return "abc"
+}
+
+fun foo(): Int {
+    var ss:String? = get()
+
+    return if (ss != null && ss.length > 0)
+        1
+    else
+        0
+}