vpp build.sh: move from "make verify" to "make pkg-verify" + "make test"

vpp build.sh: move from "make verify" to "make pkg-verify" + "make test"

Problem: The VPP CI merge and verify jobs use the "make verify", which has
special handling depending on the OS. So, to make meaningful changes
like running the test suite on more platforms, one would need
to make the changes in two places, which is error-prone and slow.

Solution: move the logic on which OS to run the "make test" into
the ci-management scripts, and stop using "make verify"

Change-Id: Icc7daa9364198f455ed8ca5bae5e5da5f15baf48
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>