Compilation failures for side-traces immediately give up on this guard.

[ptersilie]

When a side-trace fails to compile in https://github.com/ykjit/yk/blob/master/ykrt/src/mt.rs#L370 we currently don't count the failures. Instead, the guard stays in GuardState::SideTracing and thus never tries to trace this guard again. Instead, we probably want a counter similar to normal traces before we give up on a guard.