Revert of [fullcodegen] Remove the hacky %_FastOneByteArrayJoin intrinsic.

src/runtime/runtime.h

 // Copyright 2012 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.
 
 #ifndef V8_RUNTIME_RUNTIME_H_
 #define V8_RUNTIME_RUNTIME_H_
 
 #include "src/allocation.h"
 #include "src/base/platform/time.h"
 #include "src/objects.h"
@@ skipping 33 matching lines @@
   F(NewArray, -1 /* >= 3 */, 1)      \
   F(InternalArrayConstructor, -1, 1) \
   F(NormalizeElements, 1, 1)         \
   F(GrowArrayElements, 2, 1)         \
   F(HasComplexElements, 1, 1)        \
   F(IsArray, 1, 1)                   \
   F(HasCachedArrayIndex, 1, 1)       \
   F(GetCachedArrayIndex, 1, 1)       \
   F(FixedArrayGet, 2, 1)             \
   F(FixedArraySet, 3, 1)             \
+  F(FastOneByteArrayJoin, 2, 1)      \
   F(ArraySpeciesConstructor, 1, 1)
 
 
 #define FOR_EACH_INTRINSIC_ATOMICS(F) \
   F(AtomicsCompareExchange, 4, 1)     \
   F(AtomicsLoad, 2, 1)                \
   F(AtomicsStore, 3, 1)               \
   F(AtomicsAdd, 3, 1)                 \
   F(AtomicsSub, 3, 1)                 \
   F(AtomicsAnd, 3, 1)                 \
@@ skipping 1141 matching lines @@
 
 class DeclareGlobalsEvalFlag : public BitField<bool, 0, 1> {};
 class DeclareGlobalsNativeFlag : public BitField<bool, 1, 1> {};
 STATIC_ASSERT(LANGUAGE_END == 3);
 class DeclareGlobalsLanguageMode : public BitField<LanguageMode, 2, 2> {};
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_RUNTIME_RUNTIME_H_