FIX Failing AdaLoRA GPU test (#2349)
PR #2341 added more rigorous checks for AdaLoRA and adjusted the tests
to take that into account. However, one GPU test was missed. This test
is now updated too, fixing the failing nightly CI (I ran it locally on
GPU to verify).
On top of that, I adjusted some numbers on the tests so that each
AdaLoRA phase runs for 2 steps, leading to 6 steps total. This means
that tests run a little bit longer but I think it's acceptable for
better test coverage.
