ART: x86 indexOf intrinsics for the optimizing compiler

Add intrinsics implementations for indexOf in the optimizing
compiler. These are mostly ported from Quick. Add instruction
support to assemblers where necessary.

Change-Id: Ife90ed0245532a5c436a26fe84715dc357f353c8
diff --git a/compiler/utils/x86/assembler_x86.cc b/compiler/utils/x86/assembler_x86.cc
index f2541a2..7e75200 100644
--- a/compiler/utils/x86/assembler_x86.cc
+++ b/compiler/utils/x86/assembler_x86.cc
@@ -1507,6 +1507,14 @@
 }
 
 
+void X86Assembler::repne_scasw() {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0x66);
+  EmitUint8(0xF2);
+  EmitUint8(0xAF);
+}
+
+
 X86Assembler* X86Assembler::lock() {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0xF0);