Disable libunwind exceptions on release builds

[selsta]

IMHO, it is not really reasonable to just ignore these. The RandomX hugepages request alone dumps the stack every 5 minutes. That's enough to make the log file unreadable. The icing on the cake is that when build type is Release (the default), there are no debug symbols, so these stack traces are not even intelligible.

I propose that libunwind simply be disabled when build type is Release. The official binary releases already ship without it, so this would be consistent with those.

Originally posted by @ndorf in #8790

[jeffro256]

Agreed