[turbofan] Add new Float32Abs and Float64Abs operators.

src/compiler/mips/instruction-selector-mips.cc

Index: src/compiler/mips/instruction-selector-mips.cc
diff --git a/src/compiler/mips/instruction-selector-mips.cc b/src/compiler/mips/instruction-selector-mips.cc
index 149d4bc7a7dcf20d48d6f8bfe1272d8a38caee27..61a5a1cfc3f7847a3b2e8dbd0bc0b0514625e09d 100644
--- a/src/compiler/mips/instruction-selector-mips.cc
+++ b/src/compiler/mips/instruction-selector-mips.cc
@@ -463,6 +463,12 @@ void InstructionSelector::VisitFloat32Min(Node* node) { UNREACHABLE(); }
 void InstructionSelector::VisitFloat64Min(Node* node) { UNREACHABLE(); }
 
 
+void InstructionSelector::VisitFloat32Abs(Node* node) { UNREACHABLE(); }
+
+
+void InstructionSelector::VisitFloat64Abs(Node* node) { UNREACHABLE(); }
+
+
 void InstructionSelector::VisitFloat32Sqrt(Node* node) {
   VisitRR(this, kMipsSqrtS, node);
 }