PPC: [turbofan] Prevent storing signalling NaNs into holey double arrays.

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 c46ff9a6cff34c4fbb432d2f8c0fd77f0f280d80..b724001e927ff972f88a06b43ab4f14d134518a1 100644
--- a/src/compiler/ppc/instruction-selector-ppc.cc
+++ b/src/compiler/ppc/instruction-selector-ppc.cc
@@ -1294,6 +1294,10 @@ void InstructionSelector::VisitFloat32Max(Node* node) { UNREACHABLE(); }
 
 void InstructionSelector::VisitFloat64Max(Node* node) { UNREACHABLE(); }
 
+void InstructionSelector::VisitFloat64SilenceNaN(Node* node) {
+  VisitRR(this, kPPC_Float64SilenceNaN, node);
+}
+
 
 void InstructionSelector::VisitFloat32Min(Node* node) { UNREACHABLE(); }