documentclass[12pt, a4paper]{report}
usepackage{listings}
linespread{1.5}

DeclareFixedFont{ttm}{T1}{txtt}{m}{n}{10pt}

lstset{
  basicstyle=ttmlinespread{0.8},
}

begin{document}
The line spacing is perfect here.

The line spacing is perfect here too.

begin{lstlisting}
The code has
too high
line spacing
end{lstlisting}

The line spacing is perfect here.

The line spacing is perfect here too.

end{document}