bootstrap: run inspector and event loop in snapshot builder

This makes --inspect and stdin/out functional in the embedded snapshot,
currently it's not guaranteed that these work perfectly, the
plan is to investigate any out-of-sync states that might appear
in user land snapshots with this while the it is a configure-time
feature.

PR-URL: #42466
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

src/node_snapshotable.cc

@@ -15,6 +15,10 @@
 #include "node_v8.h"
 #include "node_v8_platform-inl.h"
 
+#if HAVE_INSPECTOR
+#include "inspector/worker_inspector.h"  // ParentInspectorHandle
+#endif
+
 namespace node {
 
 using v8::Context;
@@ -136,7 +140,7 @@ void SnapshotBuilder::Generate(SnapshotData* out,
                             nullptr,
                             node::EnvironmentFlags::kDefaultFlags,
                             {});
-      // TODO(joyeecheung): run env->InitializeInspector({}) here.
+
       // Run scripts in lib/internal/bootstrap/
       {
         TryCatch bootstrapCatch(isolate);
@@ -153,6 +157,9 @@ void SnapshotBuilder::Generate(SnapshotData* out,
       // could also explore snapshotting other kinds of execution modes
       // in the future).
       if (per_process::cli_options->build_snapshot) {
+#if HAVE_INSPECTOR
+        env->InitializeInspector({});
+#endif
         TryCatch bootstrapCatch(isolate);
         // TODO(joyeecheung): we could use the result for something special,
         // like setting up initializers that should be invoked at snapshot
@@ -163,7 +170,15 @@ void SnapshotBuilder::Generate(SnapshotData* out,
           PrintCaughtException(isolate, context, bootstrapCatch);
         }
         result.ToLocalChecked();
-        // TODO(joyeecheung): run SpinEventLoop here.
+        // FIXME(joyeecheung): right now running the loop in the snapshot
+        // builder seems to introduces inconsistencies in JS land that need to
+        // be synchronized again after snapshot restoration.
+        int exit_code = SpinEventLoop(env).FromMaybe(1);
+        CHECK_EQ(exit_code, 0);
+        if (bootstrapCatch.HasCaught()) {
+          PrintCaughtException(isolate, context, bootstrapCatch);
+          abort();
+        }
       }
 
       if (per_process::enabled_debug_list.enabled(DebugCategory::MKSNAPSHOT)) {