Improve consistency check between gpu vs cpu computation for general q,p-EI

[jialeiwang]

Currently unit tests for GPU implementation compare gpu vs cpu computation for general q,p-EI independently (meaning sequence of random numbers is uncontrolled). It is slow and unstable because they both use MC with limited accuracy. In this ticket we let the two sets of computations use the same set of random numbers for MC computation, and check consistency of final output.