chore: Replace testify with gotest.tools in genutil integration tests

[likhita-809]

Description

closes: #14492
ref: #12332 #14145

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[julienrbrt]

lgtm, two nits.

[atheeshp]

lgtm, couple of nits.

[atheeshp]

Can we use any of assert or require? or both are required?

[likhita-809]

we should be using only assert but there are less utilities available in gotest.tools, so I used require whenever there is a panic check since there isn't one in assert to do that.
This will be fine as of now because our main goal is to run tests standalone without any suite.

[alexanderbez]

Can't we write our own util using assert?

func AssertNotPanics(fn func())  {
  defer {
    // recover and use assert to ensure no error
  }()

  fn()
}

[likhita-809]

certainly, I could do that in next PR's and will do a follow-up for genutil tests