Motivation:
At the moment it is not possible to build netty on a power 8 systems.
Modifications:
- Improve detection of the possibility of using Conscrypt
- Skip testsuite-shading when not on x86_64 as this is the only platform for which we build tcnative atm
- Only include classifier if on x86_64 for tcnative as dependency as this is the only platform for which we build tcnative atm
- Better detect if UDT test can be run
Result:
Fixes https://github.com/netty/netty/issues/9479