Add missing headers required during non-unified build.

Unified build happens to get them included by the other sources unified
into same source file, thus didn't fail.

diff -urNp a/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp b/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
--- a/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
+++ b/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
@@ -30,6 +30,7 @@
 
 #include "BuiltinNames.h"
 #include "BytecodeGenerator.h"
+#include "BytecodeStructs.h"
 #include "CallFrame.h"
 #include "JIT.h"
 #include "JSCInlines.h"
diff -urNp a/Source/JavaScriptCore/heap/MachineStackMarker.cpp b/Source/JavaScriptCore/heap/MachineStackMarker.cpp
--- a/Source/JavaScriptCore/heap/MachineStackMarker.cpp
+++ b/Source/JavaScriptCore/heap/MachineStackMarker.cpp
@@ -23,6 +23,7 @@
 #include "MachineStackMarker.h"
 
 #include "ConservativeRoots.h"
+#include "CPU.h"
 #include "MachineContext.h"
 #include <setjmp.h>
 #include <stdlib.h>