default_system_javabase must resolve symlink

### Description of the bug:

https://github.com/enola-dev/enola/issues/1205

https://youtrack.jetbrains.com/issue/BAZEL-1788

The root cause of this ^^^ is (or might at least be partially because of, dunno if there's more after) this:

```
WARNING: Running Bazel server needs to be killed, because the following startup options are different:
- Only in old server: --default_system_javabase=/usr/lib/jvm/java-21-openjdk
- Only in new server: --default_system_javabase=/etc/alternatives/java_sdk/
Starting local Bazel server (8.3.1) and connecting to it...
```

BTW: Big THANK YOU to whoever introduced this extremely helpful new (8.3.0+) _WARNING!_

But, given that, at least on my current system (a Fedora Linux Workstation OS), the latter is "just" a symlink to the former:

```sh
$ ll /etc/alternatives/java_sdk
lrwxrwxrwx. root root 28 B 2025-06-19 06:17 /etc/alternatives/java_sdk ⇒ /usr/lib/jvm/java-21-openjdk
```

IMHO it actually should NOT _"Running Bazel server needs to be killed"_ ... because the following startup options are **actually not really** different - do you see what I mean, and agree? (Please don't hesitate to let me know if unclear, and I'm happy to elaborate further.)

I've long been looking for a good excuse to hack a bit on Bazel itself... might fix this be it - would you welcome a PR re. this? Would you like to help me get starting by pointing me to where in the code this might have to get fixed?

### Which category does this issue belong to?

Core? CLI? Configurability?

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

Probably not needed, but if you really wanted to, I guess you could (e.g. or probably even another simpler project) `git clone https://github.com/enola-dev/enola`, on a Fedora Linux Workstation (42), and run a build on the CLI and open it in IntelliJ and you should be able to see the bug.

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

Linux (Fedora, but I strongly suspect that's not relevant, and Debian et al have the same issue).

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

```
bazel info release
WARNING: Running Bazel server needs to be killed, because the following startup options are different:
- Only in old server: --default_system_javabase=/usr/lib/jvm/java-21-openjdk
- Only in new server: --default_system_javabase=/etc/alternatives/java_sdk/
Starting local Bazel server (8.3.1) and connecting to it...
release 8.3.1
```

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

N/A

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

```text
https://github.com/enola-dev/enola.git
72a0d4125486de9229749acb5bcd3fb482eba321
```

### If this is a regression, please try to identify the Bazel commit where the bug was introduced with bazelisk --bisect.

The problem was always there (for me), but only since today with the very helpful new WARNING introduced in 8.3.0 is the root cause finally clear to me.

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

No.

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

No, I'm good - but thanks for asking! 😆

Start with the --default_system_javabase startup option and reproduce the warning using /usr/lib/jvm/java-21-openjdk and the /etc/alternatives/java_sdk symlink shown in the issue. Trace the startup-option comparison and verify that equivalent symlinked paths no longer cause the Bazel server to be killed.

Written by the indexing model from the issue text.