We have 4 cores, no point running 12 threads on them

time php maintenance/rebuildLocalisationCache.php --force --threads=12
real    0m54.204s
user    1m51.353s
sys     1m21.085s

time php5 maintenance/rebuildLocalisationCache.php --force --threads=12
real    0m53.644s
user    2m19.470s
sys     0m51.810s

time php maintenance/rebuildLocalisationCache.php --force --threads=8
real    1m5.060s
user    1m41.969s
sys     1m13.215s

time php5 maintenance/rebuildLocalisationCache.php --force --threads=8
real    1m11.568s
user    2m27.809s
sys     0m49.418s

time php maintenance/rebuildLocalisationCache.php --force --threads=4
real    1m4.366s
user    1m39.950s
sys     1m9.249s

time php5 maintenance/rebuildLocalisationCache.php --force --threads=4
real    1m1.853s
user    2m32.361s
sys     0m50.005s

time php maintenance/rebuildLocalisationCache.php --force --threads=2
real    1m30.158s
user    1m42.143s
sys     1m8.987s

time php5 maintenance/rebuildLocalisationCache.php --force --threads=2
real    1m46.804s
user    2m44.827s
sys     0m45.218s

Change-Id: I58c293daf647607942e0c688e1e580871cf5df27
Merge "We have 4 cores, no point running 12 threads on them"