This patch adds an implementation of recv_vec4_pv() to the vvp_fun_concat class. This was already present in devel, so just needed to be back-ported to v0.9.
Also attached is a regression test to add to the test suite. Unfortunately this test exposes the initial 'x' vs. 'z' confusion that is still present in v0.9, so needs different gold files for devel and for v0.9.
P.S. The recent update to the pr1723367.gold file in the test suite causes a mismatch when the tests are run for v0.9. The previous version needs to be used for v0.9.