[build] Remove v8-inspector.h include from some headers

Since debug-interface.h and isolate.h only uses
v8_inspector::V8Inspector as a pointer type, this removes the #includes
and forward declares the type.

Bug: v8:11384
Change-Id: Ia361fc3a028a9abf5ee42ecb3b2575bc84a81e35
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2903159
Auto-Submit: Dan Elphick <delphick@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74648}

src/debug/debug-interface.h

@@ -7,7 +7,6 @@
 
 #include <memory>
 
-#include "include/v8-inspector.h"
 #include "include/v8-util.h"
 #include "include/v8.h"
 #include "src/base/platform/time.h"
@@ -15,6 +14,10 @@
 #include "src/debug/interface-types.h"
 #include "src/utils/vector.h"
 
+namespace v8_inspector {
+class V8Inspector;
+}  // namespace v8_inspector
+
 namespace v8 {
 
 namespace internal {

src/execution/isolate.h

@@ -13,7 +13,6 @@
 #include <unordered_map>
 #include <vector>
 
-#include "include/v8-inspector.h"
 #include "include/v8-internal.h"
 #include "include/v8-metrics.h"
 #include "include/v8.h"
@@ -48,6 +47,10 @@ class UMemory;
 }  // namespace U_ICU_NAMESPACE
 #endif  // V8_INTL_SUPPORT
 
+namespace v8_inspector {
+class V8Inspector;
+}  // namespace v8_inspector
+
 namespace v8 {
 
 namespace base {