mercury: Don't enable the .NET backend when building with mono.

The .NET IL backend is unsupported and does not build.
mercury: update 14.01 bottle.

Closes #31601.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
Update bats to 0.4.0

https://github.com/sstephenson/bats/releases/tag/v0.4.0
bats: add 0.4.0 bottle.