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

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

@@ -0,0 +1,11 @@
+// !WITH_NEW_INFERENCE
+fun foo() {
+    var v: String? = null
+    v.<!INAPPLICABLE_CANDIDATE!>length<!>
+    v = "abc"
+    v.length
+    v = null
+    v.<!UNRESOLVED_REFERENCE!>length<!>
+    v = "abc"
+    v.<!UNRESOLVED_REFERENCE!>length<!>
+}