commandutil: introduce limit stdouterr writer and flag

[sluongng]

This was splitted from #9978 to review separately.

Currently, our executor keeps remote action stdout/stderr inside
in-memory buffers. This approach can cause OOM-kill when the action
stdout/stderr are large.

Introduce a new flag to control the size of stdouterr of remote actions.
Also coupled with it is a new writer struct which returns a
ResourceExhaustedError when the limit is reached.

In a subsequent PR, we shall use this writer to modify different
isolation implementations to control the memory usage of Executor.

[bduffany]

nice

[bduffany]

maybe add:

It returns a ResourceExhausted error if a write occurs that would exceed the limit. Before returning a ResourceExhausted error, it writes as many bytes as possible before the limit would be reached.

[bduffany]

I think this can be simplified a bit

func (lw *limitWriter) Write(p []byte) (n int, err error) {
	capacity := min(lw.limit-lw.n, len(p))
	if capacity > 0 {
		n, err = lw.w.Write(p[:capacity])
		lw.n += n
	}
	

	// If we've reached the limit, return an error,
	// but don't mask the Write error if one occurred.
	if err == nil && capacity < len(p) {
		return n, status.ResourceExhaustedErrorf("stdout/stderr size exceeded limit (%d bytes)", lw.limit)
	}

	return n, err
}

do tests pass with this implementation?