Use a dictionary-mode code cache on the map rather than a dual system.

src/ic/s390/stub-cache-s390.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_S390
 
 #include "src/ic/stub-cache.h"
 #include "src/codegen.h"
 #include "src/ic/ic.h"
 #include "src/interface-descriptors.h"
@@ skipping 96 matching lines @@
 #if V8_TARGET_ARCH_S390X
   // Make sure that code is valid. The multiplying code relies on the
   // entry size being 24.
   DCHECK(sizeof(Entry) == 24);
 #else
   // Make sure that code is valid. The multiplying code relies on the
   // entry size being 12.
   DCHECK(sizeof(Entry) == 12);
 #endif
 
-  // Make sure the flags does not name a specific type.
-  DCHECK(Code::ExtractTypeFromFlags(flags) == 0);
-
   // Make sure that there are no register conflicts.
   DCHECK(!AreAliased(receiver, name, scratch, extra, extra2, extra3));
 
   // Check scratch, extra and extra2 registers are valid.
   DCHECK(!scratch.is(no_reg));
   DCHECK(!extra.is(no_reg));
   DCHECK(!extra2.is(no_reg));
   DCHECK(!extra3.is(no_reg));
 
 #ifdef DEBUG
@@ skipping 48 matching lines @@
   __ bind(&miss);
   __ IncrementCounter(counters->megamorphic_stub_cache_misses(), 1, extra2,
                       extra3);
 }
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_S390