Isolate::PrintStack: restore default verbose object printing

Review URL: https://codereview.chromium.org/1311123005

Cr-Commit-Position: refs/heads/master@{#30585}

src/heap/heap.cc

@@ -5388,7 +5388,7 @@ void Heap::RecordStats(HeapStats* stats, bool take_snapshot) {
     GetFromRingBuffer(stats->last_few_messages);
   if (stats->js_stacktrace != NULL) {
     FixedStringAllocator fixed(stats->js_stacktrace, kStacktraceBufferSize - 1);
-    StringStream accumulator(&fixed);
+    StringStream accumulator(&fixed, StringStream::kPrintObjectConcise);
     isolate()->PrintStack(&accumulator, Isolate::kPrintStackVerbose);
   }
 }

src/string-stream.h

@@ -100,7 +100,7 @@ class StringStream final {
  public:
   enum ObjectPrintMode { kPrintObjectConcise, kPrintObjectVerbose };
   StringStream(StringAllocator* allocator,
-               ObjectPrintMode object_print_mode = kPrintObjectConcise)
+               ObjectPrintMode object_print_mode = kPrintObjectVerbose)
       : allocator_(allocator),
         object_print_mode_(object_print_mode),
         capacity_(kInitialCapacity),