Create arm_blx_rel_thumb2.py

 blx thumb bug #166

suite/regress/usr/bin/arm_blx_rel_thumb2.py

+#!/usr/bin/python
+
+# This tests the relative BLX instruction for Thumb-mode
+
+# Github issue:  #166
+# Author: McLovi9
+
+from keystone import *
+
+import regress
+
+class TestARM(regress.RegressTest):
+    def runTest(self):
+        # Initialize Keystone engine
+        ks = Ks(KS_ARCH_ARM, KS_MODE_THUMB)
+        # Assemble to get back insn encoding & statement count
+        encoding, count = ks.asm(b"BLX 0xF4000134",addr=0xF400048A)
+        # Assert the result
+        self.assertEqual(encoding, [ 0xFF, 0xF7, 0x54, 0xEE ])
+
+if __name__ == '__main__':
+    regress.main()