Remove dependancy on EOSIO libtester

[ericpassmore]

[Moved over from Mandel.CDT issue 28]

Currently some of the tests are using eosio libtester for ease. But, we can and should convert those over to use the native tester framework for these as they should only be testing raw logic and not the host function implementations. Those are covered in Mandel.

For a few of the tests where we check malloc and a few others we can utilize eos-vm to create a minimal environment to test those things.