[test_script] Add specific test for legends in histograms

4 jobs for histlegends in 9 minutes and 4 seconds (queued for 4 seconds)
Status Name Job ID Coverage
  Build
passed build_linux_27 #140501
docker

00:07:35

86.0%
passed build_linux_36 #140502
docker

00:07:35

86.0%
passed build_macosx_27 #140503
macosx

00:08:57

86.0%
passed build_macosx_36 #140504
macosx

00:08:22

86.0%