When analyzing the `validate_ref_ty` ZIR instruction, an assertion would trip if the result type was a var args function argument. The fix is the same as e6b73be870 - inline the logic of `resolveType` and handle the case of var args. Closes #17494
e6b73be870
addCSourceFiles
std.Target.current
@import("builtin").target
@abs
cwd
?Build.LazyPath