Rename directory for back-end tests

compiler/testData/codegen/box/functions/tailRecursion/loops.kt

@@ -0,0 +1,14 @@
+tailRecursive fun test(x : Int, a : Any) : Int {
+    var z = if (x > 3) 3 else x
+    while (z > 0) {
+        if (z > 10) {
+            return test(x - 1, "tail")
+        }
+        test(0, "no tail")
+        z = z - 1
+    }
+
+    return 1
+}
+
+fun box() : String = if (test(100000, "test") == 1) "OK" else "FAIL"