[iwyu] Include handles.h less.

src/api-experimental.h

Index: src/api-experimental.h
diff --git a/src/api-experimental.h b/src/api-experimental.h
index bc0bc55739b503ca0cbe37d698627a081882b1d7..5b1bc1b04a2b18ce0e983c4830c8bd1f9bd25748 100644
--- a/src/api-experimental.h
+++ b/src/api-experimental.h
@@ -5,11 +5,11 @@
 #ifndef V8_API_EXPERIMENTAL_H_
 #define V8_API_EXPERIMENTAL_H_
 
-#include "src/handles.h"
-
 namespace v8 {
 namespace internal {
 class Code;
+template <typename T>
+class MaybeHandle;
 }  // internal;
 namespace experimental {
 class FastAccessorBuilder;