remove unnecessary memset in strcoll

remove unnecessary memset in strcoll

This patch avoids some initialization overhead in the hot path of strcoll by
replacing a memset with zero assignments. It improves the file listing benchmark
by 15% on x86. Tests are ok.

filelist#C              -1.30%
filelist#en_US.UTF-8    -15.08%
lorem_ipsum#vi_VN.UTF-8 -15.04%
lorem_ipsum#ar_SA.UTF-8 -11.83%
lorem_ipsum#en_US.UTF-8 -9.66%
lorem_ipsum#zh_CN.UTF-8 -8.63%
lorem_ipsum#cs_CZ.UTF-8 -8.28%
lorem_ipsum#en_GB.UTF-8 -18.07%
lorem_ipsum#da_DK.UTF-8 -11.13%
lorem_ipsum#pl_PL.UTF-8 -15.31%
lorem_ipsum#fr_FR.UTF-8 -12.26%
lorem_ipsum#pt_PT.UTF-8 -10.64%
lorem_ipsum#el_GR.UTF-8 -8.19%
lorem_ipsum#ru_RU.UTF-8 -0.65%
lorem_ipsum#iw_IL.UTF-8 -14.92%
lorem_ipsum#es_ES.UTF-8 -11.47%
lorem_ipsum#hi_IN.UTF-8 -1.05%
lorem_ipsum#sv_SE.UTF-8  6.44%
lorem_ipsum#hu_HU.UTF-8 -9.85%
lorem_ipsum#tr_TR.UTF-8 -14.96%
lorem_ipsum#is_IS.UTF-8 -10.35%
lorem_ipsum#it_IT.UTF-8 -11.33%
lorem_ipsum#sr_RS.UTF-8 -9.88%
lorem_ipsum#ja_JP.UTF-8 -3.23%

        * string/strcoll_l.c (STRCOLL): Remove unnecessary memset.