Refuse to build SMP runtime by default without native atomics

Build with fallback can be enabled by passing the `configure` command
line argument `--disable-smp-require-native-atomics`
Merge branch 'maint'

* maint:
  Add test cases for native atomics and jump table
  Refuse to build SMP runtime by default without native atomics
  Make information about use of jump table available via system_info BIF
  Make ethread library information available via system_info BIF
  Make emulator arguments available via the system_info BIF
Fix configure detection of ethread native atomics on powerpc
Merge branch 'maint'

* maint:
  Fix configure detection of ethread native atomics on powerpc