configure.ac: write summary more compactly

6 jobs for master in 175 minutes and 26 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #2207
amd64
job_clang_amd64

02:55:26

passed #2211
amd64
job_clang_amd64_nosh

02:52:26

passed #2209
amd64
job_clang_py2_amd64

02:52:25

passed #2206
amd64
job_gcc_amd64

02:09:12

passed #2210
amd64
job_gcc_amd64_nosh

02:07:41

passed #2208
amd64
job_gcc_py2_amd64

02:12:50