fix(net): solve the problem of concurrent access to syncBlockToFetch object#5832

lvs007 merged 1 commit intotronprotocol:release_v4.7.5tronprotocol/java-tron:release_v4.7.5from

zeusoo001:f-sove-access-problem-syncblockzeusoo001/java-tron:f-sove-access-problem-syncblockCopy head branch name to clipboard