Consistenly rebind loop variable in tests

[DimitrisJim]

Summary

Ref: #4413 (comment)

Though in many cases not necessary, this is a nice defensive rebinding to do in order to guard against the possibility of running things in parallel. A quick grep showed me that there's other instances where this is omitted, would be nice to get them consistent.

---

For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged/assigned

[srdtrk]

I think in this case, we should also wrap the actual test logic inside a suite.Run like this:

	for _, tc := range testCases {
		tc := tc
		suite.Run(tc.name, func() {
			suite.SetupTest()

			// ...
		})
	}