ci: verify DWARF5 symbols
ci: verify DWARF5 symbols

Technically, this does not validate the DWARF5 parsing completely, but
it looks for the `main` symbol to show up as expected when compiling
with whatever GCC version MSYS2/Git for Windows uses (which is typically
very close to the latest GCC version available).

Signed-off-by: Johannes Schindelin <53fb8db7833fca1e1746dd8592f61048d350f64c@gmx.de>

rainers/cv2pdb,rainers/cv2pdb