Revert r10908 due to flakiness and crashes.

src/hydrogen-instructions.h

 // Copyright 2012 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 1868 matching lines @@
         break;
       case kMathAbs:
         set_representation(Representation::Tagged());
         SetFlag(kFlexibleRepresentation);
         break;
       case kMathSqrt:
       case kMathPowHalf:
       case kMathLog:
       case kMathSin:
       case kMathCos:
-      case kMathTan:
         set_representation(Representation::Double());
         break;
       default:
         UNREACHABLE();
     }
     SetFlag(kUseGVN);
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* value() { return OperandAt(1); }
@@ skipping 10 matching lines @@
     } else {
       switch (op_) {
         case kMathFloor:
         case kMathRound:
         case kMathCeil:
         case kMathSqrt:
         case kMathPowHalf:
         case kMathLog:
         case kMathSin:
         case kMathCos:
-        case kMathTan:
           return Representation::Double();
         case kMathAbs:
           return representation();
         default:
           UNREACHABLE();
           return Representation::None();
       }
     }
   }
 
@@ skipping 2846 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(LoadFieldByIndex);
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_