Revert of PPC: [compiler] Drop the CompareNilIC.

src/full-codegen/ppc/full-codegen-ppc.cc

Index: src/full-codegen/ppc/full-codegen-ppc.cc
diff --git a/src/full-codegen/ppc/full-codegen-ppc.cc b/src/full-codegen/ppc/full-codegen-ppc.cc
index a5d4849c9362f7594ffbc85acb7ae9bdcfa5a949..24a2a387331f4920ec756fbee8d071e712b1b714 100644
--- a/src/full-codegen/ppc/full-codegen-ppc.cc
+++ b/src/full-codegen/ppc/full-codegen-ppc.cc
@@ -4031,11 +4031,10 @@
     __ cmp(r3, r4);
     Split(eq, if_true, if_false, fall_through);
   } else {
-    __ JumpIfSmi(r3, if_false);
-    __ LoadP(r3, FieldMemOperand(r3, HeapObject::kMapOffset));
-    __ lbz(r4, FieldMemOperand(r3, Map::kBitFieldOffset));
-    __ andi(r0, r4, Operand(1 << Map::kIsUndetectable));
-    Split(ne, if_true, if_false, fall_through, cr0);
+    Handle<Code> ic = CompareNilICStub::GetUninitialized(isolate(), nil);
+    CallIC(ic, expr->CompareOperationFeedbackId());
+    __ CompareRoot(r3, Heap::kTrueValueRootIndex);
+    Split(eq, if_true, if_false, fall_through);
   }
   context()->Plug(if_true, if_false);
 }