This is more of a comment intended to provide examples. One can construct a reasonably large class of examples of metrics on $T^2$ satisfying your property. I believe moreover that this class of metrics (described below) is stable with respect to small $C^{\infty}$ perturbation.
Infinite geodesics on surfaces without self intersections are closely connected to *geodesic lamintations*. Now, hyperbolic surfaces have plenty of geodesic laminations. So we can do the following. First take a hyperbolic metric on $T^2$ with a cusp and then smoothen the cusp close to infinity. Then there still will be a geodesic lamination in the hyperbolic part of $T^2$. For a concrete example, look at Fig 11 here: (Geodesic lamination on surfaces by Bonahon)
https://www-bcf.usc.edu/~fbonahon/Research/Preprints/StonyBrookProc.ps
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[![Fig11][1]][1]
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Fig.11. A geodesic lamination on the punctured torus.
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Or one can use a different construction, identifying a part of $T^2$ with a part of hyperbolic surface of genus $2$ as on Fig 5 in the same text. In this case one will get in infinite geodesic in $T^2$ that accumulates to two closed geodesics on both ends.
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[![Fig5][2]][2]
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I believe that both examples are stable under small perturbation of the metric.
[1]: https://i.sstatic.net/tkqtT.jpg
[2]: https://i.sstatic.net/NXRp4.jpg