regress: add a regress for issue #9 in x86_ds_default.py

suite/regress/x86_ds_default.py

+#!/usr/bin/python
+# example on how to code a Keystone regression in Python
+# Nguyen Anh Quynh, 2016
+
+# Fill in the information in the form below when you create a new regression
+
+# Github issue: #9
+# Author: Nguyen Anh Quynh
+
+from keystone import *
+
+import regress
+
+class TestX86(regress.RegressTest):
+    def runTest(self):
+        # Initialize Keystone engine
+        ks = Ks(KS_ARCH_X86, KS_MODE_32)
+        # Assemble to get back insn encoding & statement count
+        encoding, count = ks.asm("JMP DWORD PTR DS:[100]")
+        # Assert the result
+        self.assertEqual(encoding, [ 0xFF, 0x25, 0x64, 0x00, 0x00, 0x00 ])
+
+if __name__ == '__main__':
+    regress.main()