x86: handle more tricky instructions.

- support undocumented instructions FSTP & FSTPNCE. see http://blogs.technet.com/b/mmpc/archive/2013/06/24/investigation-of-a-new-undocumented-instruction-trick.aspx
- TEST instructions with opcode 0xF6, 0xF7 (MRM1r)
diff --git a/include/x86.h b/include/x86.h
index c17d922..abc13d0 100644
--- a/include/x86.h
+++ b/include/x86.h
@@ -812,6 +812,7 @@
 	X86_INS_STR,
 	X86_INS_FST,
 	X86_INS_FSTP,
+	X86_INS_FSTPNCE,
 	X86_INS_SUBPD,
 	X86_INS_SUBPS,
 	X86_INS_FSUBR,