mm/damon/tests/vaddr-kunit.h: reduce stack consumption

After "mm: move per-vma lock into vm_area_struct" we're hitting

mm/damon/tests/vaddr-kunit.h: In function 'damon_test_three_regions_in_vmas':
mm/damon/tests/vaddr-kunit.h:92:1: error: the frame size of 3280 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]

Fix by moving all those vmas off the stack.

[akpm@linux-foundation.org: fix build]
Closes: https://lkml.kernel.org/r/20241209170829.11311e70@canb.auug.org.au


Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>