Extracted getting the interp file name into a separate method `Tool::getInterpFileName`.

[KOLANICH]

[parrt]

As with my other comment... We really need to have a good reason to change something for fear we might break somebody's code that relies on the tool.

[KvanTTT]

What's the motivation of extracting the method with only single using?

[KOLANICH]

What's the motivation of extracting the method with only single using?

To make maintaining my fork with the commits implementing in-memory transpilation #3874 easier. Thanks for mentioning this! I think I need to add a comment saying that this function shouldn't be inlined.

We really need to have a good reason to change something for fear we might break somebody's code that relies on the tool.

I don't know if it is considered a good reason, but I just try to merge some of the changes (usually equivalent ones) needed for #3874 in a careful step by step way.