### What changes were proposed in this pull request?
This PR aims to make `ResourceAllocator.availableAddrs` deterministic.
### Why are the changes needed?
Currently, this function returns indeterministically due to the underlying `HashMap`. So, the test case itself is creating a list `[0, 1, 2]` initially, but ends up with comparing `[2, 1, 0]`.
Not only this happens in the 3.0.0, but also this causes UT failures on Scala 2.13 environment.
### Does this PR introduce _any_ user-facing change?
Yes, but this fixes the in-deterministic behavior.
### How was this patch tested?
- Scala 2.12: This should pass the UT with the modified test case.
- Scala 2.13: This can be tested like the following (at least `JsonProtocolSuite`)
```
$ dev/change-scala-version.sh 2.13
$ build/mvn test -pl core --am -Pscala-2.13 -Dtest=none -DwildcardSuites=org.apache.spark.deploy.JsonProtocolSuite
```
**BEFORE**
```
*** 2 TESTS FAILED ***
```
**AFTER**
```
All tests passed.
```
Closes#29281 from dongjoon-hyun/SPARK-32476.
Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
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