Prevent integer-overflow in htmlSkipBlankChars() and xmlSkipBlankChars() * HTMLparser.c: (htmlSkipBlankChars): * parser.c: (xmlSkipBlankChars): - Cap the return value at INT_MAX. - The commit range that OSS-Fuzz listed for the fix didn't make any changes to xmlSkipBlankChars(), so it seems like this issue may still exist. Found by OSS-Fuzz Issue 44803.