Description:
------------
When using SplFileObject to parse a CSV file, unexpected behaviour occurs.

According to the documentation, the DROP_NEW_LINE flag drops newlines at the end of a line.

http://php.net/manual/en/class.splfileobject.php#splfileobject.constants.drop-new-line

Tests below show that not only the new-lines at the end of the file are dropped when using the flag, but the first new line in any field is also dropped.

For example, the following raw csv:

col1,col2
testValue,one\ntwo\nthree

is interpreted like this when using DROP_NEW_LINES flag:

col1,col2
testValue,onetwo\nthree


Test script:
---------------
// Create a new CSV file using good old fputcsv:
$csvLines = [
	["Name","Notes"],
	["Person 1","This row has no new line"],
	["Person 2","This row has\nthree\nnew\nlines"],
];
$filePath = "/tmp/data.csv";
$fp = fopen($filePath, "w");

foreach($csvLines as $line) {
	fputcsv($fp, $line);
}

fclose($fp);



// Iteration 1, using DROP_NEW_LINE:

$file = new SplFileObject($filePath, "r");
$file->setFlags(
	SplFileObject::READ_CSV |
	SplFileObject::READ_AHEAD |
	SplFileObject::SKIP_EMPTY |
	SplFileObject::DROP_NEW_LINE
);

foreach($file as $i => $row) {
	printf("%d \\n in %d ... " . PHP_EOL, substr_count($row[1], "\n"), $i);;
}

echo PHP_EOL . PHP_EOL;


// Iteration 2, with no DROP_NEW_LINE flag

$file = new SplFileObject($filePath, "r");
$file->setFlags(
	SplFileObject::READ_CSV |
	SplFileObject::READ_AHEAD |
	SplFileObject::SKIP_EMPTY
);

foreach($file as $i => $row) {
	printf("%d \\n in %d ... " . PHP_EOL, substr_count($row[1], "\n"), $i);;
}

Expected result:
----------------
Expected result is that the count of newlines in each iteration is the same.

There are no newlines at the end of the lines, so there should be none dropped.

Actual result:
--------------
Output of above test script:

0 \n in 0 ... 
0 \n in 1 ... 
2 \n in 2 ... 

0 \n in 0 ... 
0 \n in 1 ... 
3 \n in 2 ... 

Actual result is that the count of newlines is always 1 less than expected. The first \n character within any field is stripped.