Stabilization of --experimental_tool_command_line

### Description of the feature request:

--experimental_tool_command_line has been unchanged for several years, and its core functionality looks trivial enough that I'm not sure there's anything to change?

### Which category does this issue belong to?

_No response_

### What underlying problem are you trying to solve with this feature?

We have a custom bazel wrapper (let's call it `bt`) and would like for it to pass on information about the invocation to Bazel so we can recall the exact invocation details in BEP consumers.

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

Linux

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

release 9.2.0

### 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` ?

```text

```

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

Not particularly, this seems like fairly disused functionality.

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

_No response_

Start by locating the --experimental_tool_command_line entry point and tracing how invocation data reaches BEP consumers. Clarify the expected behavior for a custom Bazel wrapper such as bt, then define stabilization criteria around preserving the exact invocation; the issue names no files or tests to run.

Written by the indexing model from the issue text.