Fix parsing error that contains special character.
The previous implementation replaced the `:` char with `\n`,
and split on `\n`. Test data containing strings with `\n`
were split as well. Fixes#2193.
The split function caused strings containing `\:` to add
another escape char, resulting in `\\:`. This caused the
tests with the `\:` in the string data to fail.
The fix doesn't replace with `\n`, but splits all `:` that
are not preceded with `\`. After that, removes the preceding `\` char.
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