[turbofan] Don't unconditionally read heap when printing types

... since we may be in the background. Print the HeapObjectRef instead,
which will read the heap when it's allowed to do so.

Bug: v8:9541
Change-Id: I201c6dcd83e1b050393d633e4d59aec636772da6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1889876
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64655}

src/compiler/types.cc

@@ -1022,7 +1022,7 @@ void Type::PrintTo(std::ostream& os) const {
   if (this->IsBitset()) {
     BitsetType::Print(os, this->AsBitset());
   } else if (this->IsHeapConstant()) {
-    os << "HeapConstant(" << Brief(*this->AsHeapConstant()->Value()) << ")";
+    os << "HeapConstant(" << this->AsHeapConstant()->Ref() << ")";
   } else if (this->IsOtherNumberConstant()) {
     os << "OtherNumberConstant(" << this->AsOtherNumberConstant()->Value()
        << ")";