Add tests.

python/ql/test/query-tests/Security/CWE-377/InsecureTemporaryFile.py

@@ -0,0 +1,7 @@
+from tempfile import mktemp
+
+def write_results(results):
+    filename = mktemp()
+    with open(filename, "w+") as f:
+        f.write(results)
+    print("Results written to", filename)