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

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt1571.fir.kt

@@ -0,0 +1,42 @@
+//KT-1571 Frontend fails to check val reassigment for operator overloading.
+package kt1571
+
+var c0 = 0
+var c1 = 0
+var c2 = 0
+
+class A() {
+    var p = 0
+    operator fun divAssign(a : Int) {
+        c1++;
+    }
+    operator fun times(a : Int) : A {
+        c2++;
+        return this;
+    }
+}
+
+val a : A = A()
+get() {
+    c0++
+    return field
+}
+
+fun box() : String {
+
+    a /= 3
+    if (c0 != 1) {
+        return "1"
+    }
+    if (c1 != 1) {
+        return "2"
+    }
+    <!VARIABLE_EXPECTED!>a<!> *= 3 // a = a * 3, shouldn't be able to do this on val
+    if (c0 != 2) {
+        return "3"
+    }
+    if (c2 != 1) {
+        return "4"
+    }
+    return "OK"
+}