[GLES2] Fixed some borderline case potential issues
[GLES2] Fixed some borderline case potential issues

ptitSeb/glshim,ptitSeb/gl4es,ptitSeb/gl4es,ptitSeb/glshim,ptitSeb/gl4es,ptitSeb/glshim,ptitSeb/gl4es,ptitSeb/glshim