test: make issue54343.go robust against the tiny allocator

I structured the test for issue54343.go after issue46725.go, where I
was careful to use `[4]int`, which is a type large enough to avoid the
tiny object allocator (which interferes with finalizer semantics). But
in that test, I didn't note the importance of that type, so I
mistakenly used just `int` in issue54343.go.

This CL switches issue54343.go to use `[4]int` too, and then adds
comments to both pointing out the significance of this type.

Updates #54343.

Change-Id: I699b3e64b844ff6d8438bbcb4d1935615a6d8cc4
Reviewed-on: https://go-review.googlesource.com/c/go/+/423115
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: David Chase <drchase@google.com>

0 files changed, 0 insertions, 0 deletions