[X86] shuffle-vs-trunc-128.ll - add BWVL-ONLY/VBMI/VBMI-FAST/VBMI-SLOW check...

[X86] shuffle-vs-trunc-128.ll - add BWVL-ONLY/VBMI/VBMI-FAST/VBMI-SLOW check prefixes to recover missing test checks

It is VERY annoying that update_llc_test_checks.py silently fails instead of correctly warning when this happens :(