populate_sdk_base: ensure ptest-pkgs pulls in ptest-runner

populate_sdk_base: ensure ptest-pkgs pulls in ptest-runner

Since "package_manager: Change complementary package handling to not
include soft dependencies"[1], complementary packages don't pull in
recommendations, just depends.  However, ptest.bbclass has a recommends
on ptest-runner, so if ptest packages are in an image via the ptest-pkgs
IMAGE_FEATURE, ptest-runner doesn't get installed.

[ YOCTO #14928 ]

[1] oe-core b44b0b9294675f89aa51ff84f532664f4c479677

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>