runtime: add extra subtest layer to TestFinalizerOrCleanupDeadlock

runtime: add extra subtest layer to TestFinalizerOrCleanupDeadlock

Currently TestFinalizerOrCleanupDeadlock runs a bunch of tests for both
cleanups and finalizers. However, it doesn't actually distinguish these
two cases in the subtest names. This change adds another layer of
subtest to distinguish them.

For #76523.

Change-Id: I18c2857e970cde43c18cbbcbc44e4d4ada3b2628
Reviewed-on: https://go-review.googlesource.com/c/go/+/728821
Reviewed-by: Carlos Amedee <carlos@golang.org>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Bypass: Michael Knyszek <mknyszek@google.com>