[milo] job_source -> build_source.

milo/build_source/buildbot/html_data.go

 package buildbot
 
 // We put this here because _test.go files are sometimes not built.
 var TestCases = []struct {
         Builder string
         Build   int
 }{
         {"CrWinGoma", 30608},
         {"chromium_presubmit", 426944},
         {"newline", 1234},
         {"gerritCL", 1234},
         {"win_chromium_rel_ng", 246309},
 }