Add 'bsr' instruction to x86 and x86_64

Add support for 'bsr' instruction.  Add tests.

Change-Id: I1cd8b30d7f3f5ee7fbeef8124cc6a31bf8ce59d5
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>
diff --git a/disassembler/disassembler_x86.cc b/disassembler/disassembler_x86.cc
index 9bee104..d4574f4 100644
--- a/disassembler/disassembler_x86.cc
+++ b/disassembler/disassembler_x86.cc
@@ -928,6 +928,11 @@
         has_modrm = true;
         load = true;
         break;
+      case 0xBD:
+        opcode1 = "bsr";
+        has_modrm = true;
+        load = true;
+        break;
       case 0xBE:
         opcode1 = "movsxb";
         has_modrm = true;