testexport-tarball.bb: Add recipe
This new recipe is used when exporting runtime test outside
packages that won't be installed in the testing system but
are required for the runtime testing.
This new recipe is almost identical to buildtools-tarball,
but is able to define the SDK packages in local.conf.
[YOCTO #7850]
(From OE-Core rev:
fbcd1f9ed6144a76ff6a556d23af30f04c39bfa0)
Signed-off-by: Mariano Lopez <mariano.lopez@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
