Local_test_resources doesn't actually restrict concurrency when `--local_test_jobs` is specified

### Description of the bug:

I expect the `resource::amount` tag to restrict test concurrency

### Which category does this issue belong to?

Core

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

sh_test(
name = "a",
srcs = ["test.sh"],
tags = ["resources:foo:1"],
)

sh_test(
name = "b",
srcs = ["test.sh"],
tags = ["resources:foo:1"],
)

assuming this is in the root dir, if I run `bazel test //... --local_resources=foo=1`, I'd expect test a and b to run serially, but currently they run in parallel

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

ubuntu 20.04

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

release 7.1.2

### If `bazel info release` returns `development version` or `(@non-git)`, tell us how you built Bazel.

_No response_

### What's the output of `git remote get-url origin; git rev-parse HEAD` ?

_No response_

### Is this a regression? If yes, please try to identify the Bazel commit where the bug was introduced.

_No response_

### Have you found anything relevant by searching the web?

https://github.com/bazelbuild/bazel/issues/18153

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

_No response_

Start with the local test scheduling path exercised by `sh_test` and the `--local_resources=foo=1` command, then compare the behavior with issue #18153. Reproduce the two-test example on Ubuntu with Bazel 7.1.2 and trace how `resources:foo:1` is handled when `--local_test_jobs` is set. Done means matching tagged tests no longer run concurrently under the stated resource limit, with regression coverage.

Written by the indexing model from the issue text.