Note: this "answer" is partially
(A) am going to share the result/answer as pointed by comments of my question,
(B) i need to show image not possible in comment, and
(C) maintain the flow of: question --> comment of question --> showing result.
@Andrea Aime, I tried the "buffer" parameter in WMS. It worked! Unfortunately I can not found examples/docs on how to use this "buffer" in WMS. The doc in http://docs.geoserver.org/latest/en/user/services/wms/vendor.html#buffer does not tell much about this.
So I was just guessing, I placed "buffer" in the 3rd argument of a WMS definition in OpenLayers 2 (along with layer name, format, and style).
I tried 5 different scenarios of WMS tile, as illustrated below.
It seems that meta-tiled WMS alone (B) does not completely remove the "point symbol cut" artifact as stated by @user30184.
In my observation the WMS "buffer" parameter is enough in removing the artifact, either with "meta-tile" (C) or without "meta-tile" (D).
Single tile (E) not surprisingly does not have such artifact, also as prescribed by @user30184.
Based on this observation, with the aim of completely removing "symbol cut" artifact, i have 2 option : using buffer or using single tile. I am happy that i am not cornered with only single tile as my option.