Improve CodeStubAssembler assert functionality

src/runtime/runtime-test.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include <memory>
 
 #include "src/arguments.h"
 #include "src/compiler-dispatcher/optimizing-compile-dispatcher.h"
@@ skipping 426 matching lines @@
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugPrint) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
 
   OFStream os(stdout);
 #ifdef DEBUG
-  if (args[0]->IsString()) {
+  if (args[0]->IsString() && isolate->context() != nullptr) {
     // If we have a string, assume it's a code "marker"
     // and print some interesting cpu debugging info.
     JavaScriptFrameIterator it(isolate);
     JavaScriptFrame* frame = it.frame();
     os << "fp = " << static_cast<void*>(frame->fp())
        << ", sp = " << static_cast<void*>(frame->sp())
        << ", caller_sp = " << static_cast<void*>(frame->caller_sp()) << ": ";
   } else {
     os << "DebugPrint: ";
   }
@@ skipping 336 matching lines @@
 RUNTIME_FUNCTION(Runtime_ValidateWasmOrphanedInstance) {
   HandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, instance_obj, 0);
   wasm::testing::ValidateOrphanedInstance(isolate, instance_obj);
   return isolate->heap()->ToBoolean(true);
 }
 
 }  // namespace internal
 }  // namespace v8