PPC: Use a stub in crankshaft for grow store arrays.

Port fb8e6136

Original commit message:
We were deopting without learning anything.

This is a rebase/reland of https://codereview.chromium.org/368263003

BUG=
R=mvstanton@chromium.org, dstence@us.ibm.com, michael_dawson@ca.ibm.com

Review URL: https://codereview.chromium.org/1113063002

Cr-Commit-Position: refs/heads/master@{#28177}

src/ppc/interface-descriptors-ppc.cc

@@ -54,6 +54,11 @@ const Register MathPowIntegerDescriptor::exponent() {
 }
 
 
+const Register GrowArrayElementsDescriptor::ObjectRegister() { return r3; }
+const Register GrowArrayElementsDescriptor::KeyRegister() { return r6; }
+const Register GrowArrayElementsDescriptor::CapacityRegister() { return r5; }
+
+
 void FastNewClosureDescriptor::Initialize(CallInterfaceDescriptorData* data) {
   Register registers[] = {cp, r5};
   data->Initialize(arraysize(registers), registers, NULL);