Remove grab-bag includes of v8.h from regexp engine.

src/regexp/regexp-macro-assembler-tracer.cc

Index: src/regexp/regexp-macro-assembler-tracer.cc
diff --git a/src/regexp/regexp-macro-assembler-tracer.cc b/src/regexp/regexp-macro-assembler-tracer.cc
index f07741233422f98176c8e14866e138277b0d3f5b..2abe55588e35a1d188acf4a707fc1e0c78ba68b2 100644
--- a/src/regexp/regexp-macro-assembler-tracer.cc
+++ b/src/regexp/regexp-macro-assembler-tracer.cc
@@ -2,10 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "src/v8.h"
+#include "src/regexp/regexp-macro-assembler-tracer.h"
 
 #include "src/ast.h"
-#include "src/regexp/regexp-macro-assembler-tracer.h"
 
 namespace v8 {
 namespace internal {