test/stack: remove unneeded memory allocations

test/stack: remove unneeded memory allocations

Replace the arguments array by one argument.
All objects in the args array have the same values, so there is no need
to use an array, only one struct is enough.
The args object is a lot smaller, and the allocation can be replaced
with a global variable.
As a consequence of using a single argument, there is no need to use a
loop to launch the test on every core one by one. Replace it with
rte_eal_mp_remote_launch.

The allocation of obj_table isn't needed either, because MAX_BULK is
small. The allocation can instead be replaced with a static array.

Signed-off-by: Steven Lariau <steven.lariau@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Gage Eads <gage.eads@intel.com>