add parse options added in recent libxml2 versions

--HG--
extra : transplant_source : %28%B1%7E%87%D1%E4%98%85%94xao%06%929%A6%C0%5E%1B%A1
use XML_PARSE_BIG_LINES parser option if available (libxml2 2.9.0+)

--HG--
extra : transplant_source : %96%B9%CB%8E%81h%96%1D%F6%F0E%CF%26%AD%17%9FgP%83%C7
add test for high XML line numbers

--HG--
extra : transplant_source : %0EX%40u%B3%C1m%13%B3%82%11L%2C%98X%E7%D1%E1%13%1A
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