Move DD code into its own directory (#6)

reference/tests/commands/ddtrace_run_sitecustomize.py

@@ -0,0 +1,15 @@
+import sys
+
+
+if __name__ == '__main__':
+    # detect if `-S` is used
+    suppress = len(sys.argv) == 2 and sys.argv[1] == '-S'
+    if suppress:
+        assert 'sitecustomize' not in sys.modules
+    else:
+        assert 'sitecustomize' in sys.modules
+
+    # ensure the right `sitecustomize` will be imported
+    import sitecustomize
+    assert sitecustomize.CORRECT_IMPORT
+    print('Test success')