set non-overlapping port to faucet in JsonRpcConfig default_for_tests

[puhtaytow]

Problem

Tests that engage ports binding are flaky. This is continuation of #7736

The JsonRpcConfig default_for_tests doesn't take ports from unique_port_range_for_tests in faucet case.

Summary of Changes

• JsonRpcConfig::default_for_tests now populate socket with port taken from unique_port_range_for_tests range.

[mergify]

If this PR represents a change to the public RPC API:

1. Make sure it includes a complementary update to rpc-client/ (example)
2. Open a follow-up PR to update the JavaScript client @solana/kit (example)

Thank you for keeping the RPC clients in sync with the server API @puhtaytow.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.0%. Comparing base (48c9d0c) to head (e07e914).
⚠️ Report is 5 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##           master    #7741     +/-   ##
=========================================
- Coverage    83.0%    83.0%   -0.1%     
=========================================
  Files         812      812             
  Lines      357065   357069      +4     
=========================================
- Hits       296700   296673     -27     
- Misses      60365    60396     +31     

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[alexpyattaev]

This looks appropriate, but I do not know much about faucets and possible side effects

[gregcusack]

i think you want to address port the issue here instead (may be other places too):

agave/faucet/src/faucet.rs

Lines 346 to 354 in 996570b

	// For integration tests. Listens on random open port and reports port to Sender.
	pub fn run_local_faucet(faucet_keypair: Keypair, per_time_cap: Option<u64>) -> SocketAddr {
	let (sender, receiver) = unbounded();
	run_local_faucet_with_port(faucet_keypair, sender, None, per_time_cap, None, 0);
	receiver
	.recv()
	.expect("run_local_faucet")
	.expect("faucet_addr")
	}

from my understanding, this faucet_addr in this default_for_tests() appears to always get overwritten by some passed in faucet_addr, so setting the socketaddr here won't do anything.

[puhtaytow]

I have this PR here #7736 which does address it.

[puhtaytow]

It might be strange coincidence, but i observed changes in default_for_tests() having impact on how many tests bind at random high port. I'll investigate more, turning it draft for now. Thank you.