[cluster_test] Fix printing of health-check results
[cluster_test] Fix printing of health-check results

After #1305 the health-check printing was printing one validator per line as seen below. This PR fixes it to old behaviour

Ran --health-check on my workspace and verified the expected behaviour

Related to #1244

Bug introduced by #1305

Closes: #1356
Approved by: andll

libra/libra,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core