parameterize index.translog.durability in big5

[OVI3D0]

Description

Parameterizes index.translog.durability in the big5 workload. Default is still async as the workload is intended to evaluate performance, and is not in itself a production use-case. The user can override this by passing in --workload-params=index_translog_durability:"request" for example.

Issues Resolved

#515

Testing

• New functionality includes testing

Tested by running big5 with/without new parameter

Backport to Branches:

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[gkamat]

Please add the parameter to the README file as well, with a very brief explanation of what the parameter is about ("request" flushes the transaction log after every operation to avoid data loss, while "async" batches up the changes for efficiency). Thanks.