PPC: Remove usages of Heap::NewSpaceStart and its external reference

src/crankshaft/ppc/lithium-codegen-ppc.cc

Index: src/crankshaft/ppc/lithium-codegen-ppc.cc
diff --git a/src/crankshaft/ppc/lithium-codegen-ppc.cc b/src/crankshaft/ppc/lithium-codegen-ppc.cc
index edc0d696b02d2b8de142f8e05a53ef947ed3a7a8..425ac7ea80f6b50c521b18e95af75fc03b527c9d 100644
--- a/src/crankshaft/ppc/lithium-codegen-ppc.cc
+++ b/src/crankshaft/ppc/lithium-codegen-ppc.cc
@@ -4487,9 +4487,10 @@ void LCodeGen::DoTransitionElementsKind(LTransitionElementsKind* instr) {
 
 void LCodeGen::DoTrapAllocationMemento(LTrapAllocationMemento* instr) {
   Register object = ToRegister(instr->object());
-  Register temp = ToRegister(instr->temp());
+  Register temp1 = ToRegister(instr->temp1());
+  Register temp2 = ToRegister(instr->temp2());
   Label no_memento_found;
-  __ TestJSArrayForAllocationMemento(object, temp, &no_memento_found);
+  __ TestJSArrayForAllocationMemento(object, temp1, temp2, &no_memento_found);
   DeoptimizeIf(eq, instr, Deoptimizer::kMementoFound);
   __ bind(&no_memento_found);
 }