gpgscm: Remove dubious stack implementation.
* tests/gpgscm/scheme-private.h (struct scheme): Remove related fields. * tests/gpgscm/scheme.c: Drop all !USE_SCHEME_STACK code. * tests/gpgscm/scheme.h (USE_SCHEME_STACK): Remove macro.
- Signed-off-by: Justus Winter <justus@g10code.com>