CI: disable sunmd5 tests on ARM architecture

SunMD5 format crashes on ARM (macOS and Linux)
See #5296.

Signed-off-by: Claudio André <claudioandre.br@gmail.com>

.ci/disable_formats.sh

@@ -11,6 +11,10 @@ echo 'KeePass-opencl = Y' >> ../run/john-local.conf
 # These formats fail OpenCL CPU runtime
 echo 'RAR-opencl = Y' >> ../run/john-local.conf
 
+# SunMD5 format crashes on ARM. macOS and Linux
+# See https://github.com/openwall/john/issues/5296
+echo 'sunmd5 = Y' >> ../run/john-local.conf
+
 # These formats run very slowly inside CI
 # Time measures are from Intel CPU driver running inside Docker
 echo 'ansible-opencl = Y' >> ../run/john-local.conf    # (282.202952 secs) PASS