[turbofan] Float32Abs and Float64Abs are supported by all backends.

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

Index: src/compiler/ppc/instruction-selector-ppc.cc
diff --git a/src/compiler/ppc/instruction-selector-ppc.cc b/src/compiler/ppc/instruction-selector-ppc.cc
index e3003eddf837e2ed8d12a712c6b6c15fa0d459c2..afe30d4c8591b4673aad949e887ff06720490762 100644
--- a/src/compiler/ppc/instruction-selector-ppc.cc
+++ b/src/compiler/ppc/instruction-selector-ppc.cc
@@ -1623,10 +1623,8 @@ void InstructionSelector::VisitFloat64InsertHighWord32(Node* node) {
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {
-  return MachineOperatorBuilder::kFloat32Abs |
-         MachineOperatorBuilder::kFloat32Max |
+  return MachineOperatorBuilder::kFloat32Max |
          MachineOperatorBuilder::kFloat32Min |
-         MachineOperatorBuilder::kFloat64Abs |
          MachineOperatorBuilder::kFloat64Max |
          MachineOperatorBuilder::kFloat64Min |
          MachineOperatorBuilder::kFloat64RoundDown |