[ISSUE #3467] Fail fast on loading files with error mappedFileSize

[Jason918]

Make sure set the target branch to develop

What is the purpose of the change

Just revert the merge error with previous commits in #3357

Brief changelog

Revert 2 lines in org.apache.rocketmq.store.MappedFileQueue#doLoad

Verifying this change

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[Jason918]

@duhengforever @RongtongJin @yuz10 PTAL