Run fewer testcases in diameter_traffic_SUITE
Run fewer testcases in diameter_traffic_SUITE

Instead of even trying to run a meaningful subset of all the
configuration possibilities, just choose one and simplify the
common_test mechanics/workarounds. The test suite is run night after
night on many different hosts, so simply choosing a configuration
results in coverage over time.

jj1bdx/otp,mikpe/otp,rlipscombe/otp,emacsmirror/erlang,mikpe/otp,dgud/otp,jj1bdx/otp,isvilen/otp,dgud/otp,dumbbell/otp,g-andrade/otp,erlang/otp,dumbbell/otp,vinoski/otp,erlang/otp,isvilen/otp,bjorng/otp,rlipscombe/otp,isvilen/otp,bjorng/otp,jj1bdx/otp,bjorng/otp,dumbbell/otp,vinoski/otp,g-andrade/otp,potatosalad/otp,emacsmirror/erlang,g-andrade/otp,dumbbell/otp,potatosalad/otp,potatosalad/otp,mikpe/otp,mikpe/otp,dgud/otp,rlipscombe/otp,dgud/otp,emacsmirror/erlang,emacsmirror/erlang,dumbbell/otp,isvilen/otp,vinoski/otp,dgud/otp,mikpe/otp,erlang/otp,g-andrade/otp,bjorng/otp,bjorng/otp,mikpe/otp,rlipscombe/otp,potatosalad/otp,bjorng/otp,emacsmirror/erlang,vinoski/otp,isvilen/otp,erlang/otp,isvilen/otp,emacsmirror/erlang,vinoski/otp,dumbbell/otp,jj1bdx/otp,rlipscombe/otp,dumbbell/otp,jj1bdx/otp,g-andrade/otp,rlipscombe/otp,g-andrade/otp,jj1bdx/otp,dumbbell/otp,isvilen/otp,rlipscombe/otp,jj1bdx/otp,g-andrade/otp,potatosalad/otp,bjorng/otp,dumbbell/otp,vinoski/otp,bjorng/otp,dgud/otp,g-andrade/otp,isvilen/otp,potatosalad/otp,erlang/otp,bjorng/otp,rlipscombe/otp,erlang/otp,g-andrade/otp,jj1bdx/otp,erlang/otp,dumbbell/otp,rlipscombe/otp,bjorng/otp,isvilen/otp,emacsmirror/erlang,erlang/otp,mikpe/otp,dgud/otp,vinoski/otp,emacsmirror/erlang,dgud/otp,dgud/otp,potatosalad/otp,potatosalad/otp,vinoski/otp,isvilen/otp,potatosalad/otp,erlang/otp,dgud/otp,emacsmirror/erlang,vinoski/otp,rlipscombe/otp,vinoski/otp,jj1bdx/otp,g-andrade/otp,mikpe/otp,emacsmirror/erlang,potatosalad/otp,mikpe/otp,mikpe/otp,erlang/otp,jj1bdx/otp