dotnet dump collect no pause/wait for GC (invalid method table)

### Description

A large, full dump was taken of a process to figure out some memory leaks (16gb), using `dotnet dump collect`. However analyzing that now I'm getting this:

```
> dumpheap
The garbage collector data structures are not in a valid state for traversal.
It is either in the "plan phase," where objects are being moved around, or
we are at the initialization or shutdown of the gc heap. Commands related to
displaying, finding or traversing objects as well as gc heap segments may not
work properly. !dumpheap and !verifyheap may incorrectly complain of heap
consistency errors.
Address MT Size
Object 00007f4dc3fff000 has an invalid method table.
```

I think dotnet-dump should be waiting for GC Idle then freezing the process no?

### Configuration

.NET Core 3.1, Linux.