Rename directory for back-end tests

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

@@ -0,0 +1,21 @@
+tailRecursive fun test(x : Int, e : Any) : Unit {
+    if (x == 1) {
+        test(x - 1, "tail")
+    } else if (x == 2) {
+        test(x - 1, "tail")
+        return
+    } else if (x == 3) {
+        test(x - 1, "no tail")
+        if (x == 3) {
+            test(x - 1, "tail")
+        }
+        return
+    } else if (x > 0) {
+        test(x - 1, "tail")
+    }
+}
+
+fun box() : String {
+    test(1000000, "test")
+    return "OK"
+}