Add missing semicolon in backtrace debug code.
Add missing semicolon in backtrace debug code.

Apparently backtrace has not been used for debugging since it was broken in 7fba1f0b.

Even though this is test code it might be good to find a way to test it to prevent regressions.

pgbackrest/pgbackrest,pgmasters/backrest,pgbackrest/pgbackrest,pgmasters/backrest,pgbackrest/pgbackrest