[turbofan] Implemented the optional Float32RoundTiesEven 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 90d399afae7d884aeb8334a7df26ced74c38f9b6..ff5eff094c9a0c66f5c40ea8e3e0de55e60033a7 100644
--- a/src/compiler/ppc/instruction-selector-ppc.cc
+++ b/src/compiler/ppc/instruction-selector-ppc.cc
@@ -1159,6 +1159,11 @@ void InstructionSelector::VisitFloat64RoundTiesAway(Node* node) {
 }
 
 
+void InstructionSelector::VisitFloat32RoundTiesEven(Node* node) {
+  UNREACHABLE();
+}
+
+
 void InstructionSelector::VisitFloat64RoundTiesEven(Node* node) {
   UNREACHABLE();
 }