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

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

Index: src/ic/s390/stub-cache-s390.cc
diff --git a/src/ic/s390/stub-cache-s390.cc b/src/ic/s390/stub-cache-s390.cc
index 054b946df849233cdbaa7487aa5c9408503c11c6..1dc5c8d0ea2cb1eb5ce8696550fbf6b14ee6a1cf 100644
--- a/src/ic/s390/stub-cache-s390.cc
+++ b/src/ic/s390/stub-cache-s390.cc
@@ -114,9 +114,6 @@ void StubCache::GenerateProbe(MacroAssembler* masm, Code::Kind ic_kind,
   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));