Remove usage of validator function in eval_test.go

[lucifercr07]

Issue:

• We've migrated all the commands to new eval format, however we still have few unit test cases still using old output format.
  

As part of this issue:

1. Analyse the references of validator func(output []byte) in evalTestCase struct.
2. Remove the reference and update the test cases to implement newValidator func(output interface{})
3. If all the references are removed, we can delete the validator func(output []byte) from evalTestCase struct.

[c-harish]

@lucifercr07, Can i pick this up?

[lucifercr07]

@c-harish assigned, thanks for contributing.

[ChetanNagane]

Hi @c-harish i believe you already have issue in your hand #1250 can you please let me take up this issue.

[c-harish]

Hi @c-harish i believe you already have issue in your hand #1250 can you please let me take up this issue.

Hi, @ChetanNagane. I have a blocker on #1250. So went ahead with his one.