[debuginfo-tests] Recommit test sret.cpp

This test was accidently removed when the directory structure was shuffled
around for dexter in f78c236efda8.

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D96968

GitOrigin-RevId: 54b6d01685ef3b3bce4f0b1e9262291a9d535725
1 file changed