[turbofan] Introduce simplified operator NumberAbs.

src/compiler/opcodes.h

 // Copyright 2013 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.
 
 #ifndef V8_COMPILER_OPCODES_H_
 #define V8_COMPILER_OPCODES_H_
 
 #include <iosfwd>
 
 // Opcodes for control operators.
@@ skipping 182 matching lines @@
   V(NumberMultiply)                   \
   V(NumberDivide)                     \
   V(NumberModulus)                    \
   V(NumberBitwiseOr)                  \
   V(NumberBitwiseXor)                 \
   V(NumberBitwiseAnd)                 \
   V(NumberShiftLeft)                  \
   V(NumberShiftRight)                 \
   V(NumberShiftRightLogical)          \
   V(NumberImul)                       \
+  V(NumberAbs)                        \
   V(NumberClz32)                      \
   V(NumberCeil)                       \
   V(NumberCos)                        \
   V(NumberFloor)                      \
   V(NumberFround)                     \
   V(NumberAtan)                       \
   V(NumberAtan2)                      \
   V(NumberAtanh)                      \
   V(NumberExp)                        \
   V(NumberExpm1)                      \
@@ skipping 473 matching lines @@
   }
 };
 
 std::ostream& operator<<(std::ostream&, IrOpcode::Value);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_OPCODES_H_