gpgme, libgcrypt tests are always skipped with newer versions

[thesamesam]

Since the following commits, the GnuPG stack doesn't use NIH -config tools anymore in common cases:

• 0b47de9c719b0ed0da0791f0525de073737bde5a in libgpg-error
• 2db5b5e995c21c5bd9cd193c2ed1109ba9b1a440 in libgcrypt
• 02a2f350359013bf33c3957e95c98726273ced8c in gpgme

It still uses them if libgpg-error is configured to install them but many installations won't have these files anymore.

In test cases/frameworks/27 gpgme/meson.build, we have:

wm = find_program('gpgme-config', required: false)
if not wm.found()
  error('MESON_SKIP_TEST: gpgme-config not installed')
endif

And the same in test cases/frameworks/24 libgcrypt/meson.build. We'll skip these very often as a result of the above.