vppinfra: deprecate test_mheap.c

The original mheap allocator found the exit a long time ago,
move test_mheap.c to .../extras/deprecated/vppinfra

Type: test

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: Ib1ed40ac605ad76f33c22a681a6df867985bbbba

diff --git a/src/vppinfra/test_mheap.c b/extras/deprecated/vppinfra/test_mheap.c
similarity index 100%
rename from src/vppinfra/test_mheap.c
rename to extras/deprecated/vppinfra/test_mheap.c