Assert that context creation doesn't throw

src/debug/debug.cc

Index: src/debug/debug.cc
diff --git a/src/debug/debug.cc b/src/debug/debug.cc
index 6969c06a17d752797851f4d95dd68e49b1bfb9fc..924ea9494f942f3e82b6e103556588eaa33b196d 100644
--- a/src/debug/debug.cc
+++ b/src/debug/debug.cc
@@ -655,7 +655,9 @@ MaybeHandle<Object> Debug::CallFunction(const char* name, int argc,
   Handle<JSFunction> fun = Handle<JSFunction>::cast(
       JSReceiver::GetProperty(isolate_, holder, name).ToHandleChecked());
   Handle<Object> undefined = isolate_->factory()->undefined_value();
-  return Execution::TryCall(isolate_, fun, undefined, argc, args);
+  MaybeHandle<Object> maybe_exception;
+  return Execution::TryCall(isolate_, fun, undefined, argc, args,
+                            &maybe_exception);
 }
 
 
@@ -2491,8 +2493,9 @@ v8::Local<v8::String> MessageImpl::GetJSON() const {
       return v8::Local<v8::String>();
     }
 
-    MaybeHandle<Object> maybe_json =
-        Execution::TryCall(isolate, fun, event_data_, 0, NULL);
+    MaybeHandle<Object> maybe_exception;
+    MaybeHandle<Object> maybe_json = Execution::TryCall(
+        isolate, fun, event_data_, 0, nullptr, &maybe_exception);
     Handle<Object> json;
     if (!maybe_json.ToHandle(&json) || !json->IsString()) {
       return v8::Local<v8::String>();