PHPLIB-663: Update aggregate-let spec test (#833)
PHPLIB-663: Update aggregate-let spec test (#833)

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jmikola/mongo-php-library,jmikola/mongo-php-library,mongodb/mongo-php-library,mongodb/mongo-php-library,10gen-labs/mongo-php-library-prototype,mongodb/mongo-php-library,mongodb/mongo-php-library,jmikola/mongo-php-library,jmikola/mongo-php-library,jmikola/mongo-php-library-prototype