Revert r38116 because of crashes.

runtime/vm/assembler_ia32.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/cpu.h"
@@ skipping 1756 matching lines @@
 
 
 void Assembler::bsrl(Register dst, Register src) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x0F);
   EmitUint8(0xBD);
   EmitRegisterOperand(dst, src);
 }
 
 
-void Assembler::bt(Register base, Register offset) {
-  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
-  EmitUint8(0x0F);
-  EmitUint8(0xA3);
-  EmitRegisterOperand(offset, base);
-}
-
-
 void Assembler::enter(const Immediate& imm) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0xC8);
   ASSERT(imm.is_uint16());
   EmitUint8(imm.value() & 0xFF);
   EmitUint8((imm.value() >> 8) & 0xFF);
   EmitUint8(0x00);
 }
 
 
@@ skipping 923 matching lines @@
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfXmmRegisters));
   return xmm_reg_names[reg];
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32