[m-rev.] for possible review: use explicit streams in the MLDS backend

[Julien Fischer]

Hi Zoltan,

On Mon, 16 Nov 2020, Zoltan Somogyi wrote:

> Does anyone want to review this? It contains more of the same kinds
> of changes as the previous diff, and it is pretty boring.

It was ;-)

> It has bootchecked in hlc.gc, csharp and java grades. In the last two
> grades, it had a few more test failures than the last bootchecks I did
> in those grades, but I haven't seen any evidence that they were caused
> by this change.

If it was the string format tests, I committed a fix for them yesterday.

The diff looks fine.

Julien.