web3-core-requestmanager: Use sendAsync when available in sendBatch

[iamdoron]

No description provided.

[coveralls]

Coverage remained the same at 85.55% when pulling 48b73c7 on iamdoron:1.0 into 17e1631 on ethereum:1.0.

[frozeman]

In new web3.js version the send IS async. so only send should be used. When the provider is added it should take care of making sure sendAsync is translated to send. So this logic should be rather there.

[iamdoron]

@frozeman Thanks for the reply. The problem is that some providers in the wild are not compatible, and you already doing it for regular send: https://github.com/iamdoron/web3.js/blob/48b73c70fe00745176a836725442f45ab5378e83/packages/web3-core-requestmanager/src/index.js#L129
(cf013f5)
my actual problem is when using the Ganache test provider, as it doesn't support send

[frozeman]

Youre right, it added that as a fallback, when as i only change that for the web3.currentProvider which is already existing. Will merge,