[SCB-1184] add IT for the case that provider's response type is CompletableFuture<ResponseEntity>

[yhs0092]

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• add IT
• limit memory consumption of IT

[coveralls]

Coverage increased (+0.03%) to 85.697% when pulling 54390ce on yhs0092:add_it_for_CompletableFuture_ReponseEntity_case into 90149fb on apache:master.