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

compiler/testData/diagnostics/tests/reassignment/whiletrue.fir.kt

@@ -0,0 +1,11 @@
+// !DIAGNOSTICS: -UNUSED_VALUE
+
+fun foo(): Int {
+    val i: Int
+    var j = 0
+    while (true) {
+        i = ++j
+        if (j > 5) break
+    } 
+    return i
+}