Drop unused rdtsc instruction.

test/cctest/test-disasm-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 77 matching lines @@
   __ cmpb(rbx, Operand(rbp, rcx, times_2, 0));
   __ cmpb(Operand(rbp, rcx, times_2, 0), rbx);
   __ or_(rdx, Immediate(3));
   __ xor_(rdx, Immediate(3));
   __ nop();
   {
     CHECK(CpuFeatures::IsSupported(CPUID));
     CpuFeatures::Scope fscope(CPUID);
     __ cpuid();
   }
-  {
-    CHECK(CpuFeatures::IsSupported(RDTSC));
-    CpuFeatures::Scope fscope(RDTSC);
-    __ rdtsc();
-  }
   __ movsxbq(rdx, Operand(rcx, 0));
   __ movsxwq(rdx, Operand(rcx, 0));
   __ movzxbl(rdx, Operand(rcx, 0));
   __ movzxwl(rdx, Operand(rcx, 0));
   __ movzxbq(rdx, Operand(rcx, 0));
   __ movzxwq(rdx, Operand(rcx, 0));
 
   __ nop();
   __ imul(rdx, rcx);
   __ shld(rdx, rcx);
@@ skipping 300 matching lines @@
   CHECK(code->IsCode());
 #ifdef OBJECT_PRINT
   Code::cast(code)->Print();
   byte* begin = Code::cast(code)->instruction_start();
   byte* end = begin + Code::cast(code)->instruction_size();
   disasm::Disassembler::Disassemble(stdout, begin, end);
 #endif
 }
 
 #undef __