unittests: Print output for failing commands
unittests: Print output for failing commands

Because we are using check_output, if the command fails no output will
be printed at all. So, we use subprocess.run instead.

Also, on configure failures, print the meson-log.txt instead of stdout.

mesonbuild/meson,MathieuDuponchelle/meson,mesonbuild/meson,wberrier/meson,aaronp24/meson,aaronp24/meson,MathieuDuponchelle/meson,becm/meson,QuLogic/meson,mesonbuild/meson,pexip/meson,trhd/meson,pexip/meson,pexip/meson,wberrier/meson,pexip/meson,jeandet/meson,ernestask/meson,trhd/meson,pexip/meson,jpakkane/meson,fmuellner/meson,becm/meson,thiblahute/meson,QuLogic/meson,wberrier/meson,wberrier/meson,MathieuDuponchelle/meson,QuLogic/meson,trhd/meson,thiblahute/meson,rhd/meson,rhd/meson,fmuellner/meson,becm/meson,aaronp24/meson,thiblahute/meson,MathieuDuponchelle/meson,wberrier/meson,aaronp24/meson,becm/meson,jeandet/meson,thiblahute/meson,aaronp24/meson,QuLogic/meson,rhd/meson,aaronp24/meson,aaronp24/meson,MathieuDuponchelle/meson,fmuellner/meson,fmuellner/meson,ernestask/meson,mesonbuild/meson,pexip/meson,jeandet/meson,rhd/meson,thiblahute/meson,trhd/meson,jpakkane/meson,jpakkane/meson,jeandet/meson,trhd/meson,trhd/meson,pexip/meson,QuLogic/meson,rhd/meson,ernestask/meson,rhd/meson,becm/meson,MathieuDuponchelle/meson,becm/meson,aaronp24/meson,MathieuDuponchelle/meson,jeandet/meson,ernestask/meson,mesonbuild/meson,jeandet/meson,fmuellner/meson,pexip/meson,mesonbuild/meson,MathieuDuponchelle/meson,mesonbuild/meson,QuLogic/meson,wberrier/meson,aaronp24/meson,QuLogic/meson,ernestask/meson,mesonbuild/meson,becm/meson,mesonbuild/meson,mesonbuild/meson,becm/meson,trhd/meson,jpakkane/meson,thiblahute/meson,pexip/meson,thiblahute/meson,thiblahute/meson,jeandet/meson,ernestask/meson,jeandet/meson,becm/meson,jpakkane/meson,trhd/meson,ernestask/meson,QuLogic/meson,jpakkane/meson,jpakkane/meson,wberrier/meson,rhd/meson,jeandet/meson,fmuellner/meson,fmuellner/meson,QuLogic/meson,ernestask/meson,fmuellner/meson,becm/meson,fmuellner/meson,jpakkane/meson,jpakkane/meson,MathieuDuponchelle/meson,ernestask/meson,trhd/meson,wberrier/meson,rhd/meson,pexip/meson,thiblahute/meson