There is not really enough information on the data sheet to allow you to answer this question accurately. 

I would expect it to look a bit like the [7805][1] input-output characteristics:

[![enter image description here][2]][2] 

[Figure 5][3] in the datasheet shows you where the output voltage *starts* to decline linearly, but I see no information on what happens at the output as the input voltage approaches zero. At some point it will likely drop to near zero, similar to the LM340 aka 7805.

So the output waveform would stay at zero for a spell, zoom up to some voltage, increase like a segment of a sine wave until the output hits 5.0V (at which point the input will be somewhat higher) and flat-line until the input falls again to the drop-out voltage at the output current (in your case, just the resistors form the load). 


  [1]: https://www.ti.com/lit/ds/symlink/lm7800.pdf?ts=1593618956546&ref_url=https%253A%252F%252Fwww.google.ca%252F
  [2]: https://i.sstatic.net/4V3jS.jpg
  [3]: https://www.ti.com/lit/ds/symlink/lm317.pdf