[stubs] Reduce number of StoreTransitionStub instances.

src/ic/s390/handler-compiler-s390.cc

Index: src/ic/s390/handler-compiler-s390.cc
diff --git a/src/ic/s390/handler-compiler-s390.cc b/src/ic/s390/handler-compiler-s390.cc
index d45dcbf225c7c3aa516646000c4b49aef9546c44..504bacebaf3f24cdad475ee57a0a801b7eebcc81 100644
--- a/src/ic/s390/handler-compiler-s390.cc
+++ b/src/ic/s390/handler-compiler-s390.cc
@@ -125,9 +125,13 @@ void PropertyHandlerCompiler::DiscardVectorAndSlot() {
   __ la(sp, MemOperand(sp, 2 * kPointerSize));
 }
 
-void PropertyHandlerCompiler::PushReturnAddress(Register tmp) { UNREACHABLE(); }
+void PropertyHandlerCompiler::PushReturnAddress(Register tmp) {
+  // No-op. Return address is in lr register.
+}
 
-void PropertyHandlerCompiler::PopReturnAddress(Register tmp) { UNREACHABLE(); }
+void PropertyHandlerCompiler::PopReturnAddress(Register tmp) {
+  // No-op. Return address is in lr register.
+}
 
 void PropertyHandlerCompiler::GenerateDictionaryNegativeLookup(
     MacroAssembler* masm, Label* miss_label, Register receiver,