chore: cleaunp `grind` tests

Tests using `logInfo` were taking an additional two seconds on my
machine. This is a performance issue with the old code generator,
where we spend all this time specializing the logging functions for
`GoalM`. I have not checked whether the new code generator is also
affected by this performance issue.

Here is a small example that exposes the issue:
```lean
import Lean

set_option profiler true
open Lean Meta Grind in
def test (e : Expr): GoalM Unit := do
  logInfo e
```

cc @zwarich