Allow for adjustment of highWaterMark on child_process.spawn().stdout

[realies]

A revival of #41611.

Adding configurable output chunk size with support for backpressure in child_process.spawn().stdout can improve memory efficiency and allow the use of components that expect a maximum chunk size input.

[realies]

@targos, do you know if it is likely that the following merged PRs have brought this functionality closer to possible?

• stream: add setter & getter for default highWaterMark #46929
• Fix atomics to use C11 where possible libuv/libuv#3950

I can see that this feature request is still open, but I don't know if it's still needed:

• Support queuing work from a worker thread (feature request) libuv/libuv#3422

[fabiospampinato]

It'd be nice if this issue received some attention. It's a relatively important issue which may not be too difficult to address.