[iwyu] Include handles.h less.

src/source-position-table.h

Index: src/source-position-table.h
diff --git a/src/source-position-table.h b/src/source-position-table.h
index f569ac9819a97721269b7a2f8fa6c274cd9a2f90..756838d1e510b033e8f3f171a0c077bf31fecb23 100644
--- a/src/source-position-table.h
+++ b/src/source-position-table.h
@@ -8,7 +8,6 @@
 #include "src/assert-scope.h"
 #include "src/checks.h"
 #include "src/globals.h"
-#include "src/handles.h"
 #include "src/source-position.h"
 #include "src/zone/zone-containers.h"
 
@@ -18,6 +17,8 @@ namespace internal {
 class AbstractCode;
 class BytecodeArray;
 class ByteArray;
+template <typename T>
+class Handle;
 class Isolate;
 class Zone;