Add failing test for unbounded loop

Author: Noblix

tests/for-unbounded-bad.slang

@@ -0,0 +1,15 @@
+method client(n: Int)
+    requires n >= 0
+{
+    var counter: Int := 0;
+    for i in 0..n
+        // @CheckError 
+        invariant counter == i
+    {
+        counter := counter + 1;
+        match {
+            i == 10 => counter := 0
+        }
+    };
+    assert counter == n
+}