Move tests in basic/tests/ up one level preparating to multiple test dirs.

tests/basics/for1.py

@@ -0,0 +1,19 @@
+# basic for loop
+
+def f():
+    for x in range(2):
+        for y in range(2):
+            for z in range(2):
+                print(x, y, z)
+
+f()
+
+# range with negative step
+for i in range(3, -1, -1):
+    print(i)
+
+a = -1
+# range with non-constant step - we optimize constant steps, so this
+# will be executed differently
+for i in range(3, -1, a):
+    print(i)