MIPS: [Atomics] Remove Atomics code stubs; use TF ops.

src/mips64/simulator-mips64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <cmath>
 
 #if V8_TARGET_ARCH_MIPS64
@@ skipping 3801 matching lines @@
       break;
     case TLTU:
       do_interrupt = rs_u() < rt_u();
       break;
     case TEQ:
       do_interrupt = rs() == rt();
       break;
     case TNE:
       do_interrupt = rs() != rt();
       break;
+    case SYNC:
+      // TODO(palfia): Ignore sync instruction for now.
+      break;
     // Conditional moves.
     case MOVN:
       if (rt()) {
         SetResult(rd_reg(), rs());
       }
       break;
     case MOVCI: {
       uint32_t cc = get_instr()->FBccValue();
       uint32_t fcsr_cc = get_fcsr_condition_bit(cc);
       if (get_instr()->Bit(16)) {  // Read Tf bit.
@@ skipping 1057 matching lines @@
 }
 
 
 #undef UNSUPPORTED
 }  // namespace internal
 }  // namespace v8
 
 #endif  // USE_SIMULATOR
 
 #endif  // V8_TARGET_ARCH_MIPS64