`Create symlink tree out-of-process` is only limited by `--jobs`

### Description of the bug:

With a high `--jobs` value, multiple `Create symlink tree out-of-process` can starve the system of resources, resulting in much longer builds.

Ideally this should be limited to `HOST_CPUS`, `--local_cpu_resources`, or a new disk related resource.

### Which category does this issue belong to?

Local Execution, Performance

### What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

Have a resource constrained machine (possibly a VM), set a high `--jobs` value, have lots of targets that have runfiles (which will then `Create symlink tree out-of-process`), and then build. You will see that symlink tree creation that usually takes a couple seconds max can now take over a 1000 seconds:


### Which operating system are you running Bazel on?

macOS

### What is the output of `bazel info release`?

release 7.0.2

### Any other information, logs, or outputs that you want to share?

I know that in the future Loom will decouple `--jobs` from the number of maximum downloads or remote actions performed, which could sidestep this issue for us. But I'm not sure we need to wait for that to fix this issue.