[iwyu] Include handles.h less.

src/fast-accessor-assembler.h

Index: src/fast-accessor-assembler.h
diff --git a/src/fast-accessor-assembler.h b/src/fast-accessor-assembler.h
index c1380c90258169bcba6ffe6dd0a93159463fba94..f51d5a79e829eb4db2da4026ed799b168af06123 100644
--- a/src/fast-accessor-assembler.h
+++ b/src/fast-accessor-assembler.h
@@ -11,7 +11,7 @@
 
 #include "include/v8-experimental.h"
 #include "src/base/macros.h"
-#include "src/handles.h"
+#include "src/zone/zone.h"
 
 namespace v8 {
 namespace internal {
@@ -19,7 +19,8 @@ namespace internal {
 class Code;
 class CodeStubAssembler;
 class Isolate;
-class Zone;
+template <typename T>
+class MaybeHandle;
 
 namespace compiler {
 class Node;