[turbofan] introduce Int32/64AbsWithOverflow optional operator

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 181436440fa2de3f071adf302493961cef21fabd..ca418b793e35e73e4ac59a4664c5a5d960d0bc77 100644
--- a/src/compiler/ppc/instruction-selector-ppc.cc
+++ b/src/compiler/ppc/instruction-selector-ppc.cc
@@ -2123,6 +2123,14 @@ void InstructionSelector::VisitAtomicCompareExchange(Node* node) {
   UNIMPLEMENTED();
 }
 
+void InstructionSelector::VisitInt32AbsWithOverflow(Node* node) {
+  UNREACHABLE();
+}
+
+void InstructionSelector::VisitInt64AbsWithOverflow(Node* node) {
+  UNREACHABLE();
+}
+
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {