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

compiler/testData/diagnostics/tests/smartCasts/loops/nestedLoops.fir.kt

@@ -0,0 +1,17 @@
+fun x(): Boolean { return true }
+
+public fun foo(p: String?, r: String?, q: String?): Int {
+    while(true) {
+        q!!.length
+        do {
+            do {
+                p!!.length
+            } while (!x())
+        } while (r == null)
+        if (!x()) break
+    }
+    // Smart cast is possible everywhere
+    r.<!INAPPLICABLE_CANDIDATE!>length<!>
+    q.length
+    return p.length
+}