[CIR][NFC] Fix shared library build caused by interface->IR dependence

[tommymcm]

After #1878, we introduced a dependency from the LoopOpInterface on BreakOp.

A similar dependency was resolved for ConditionOp by introducing a ConditionOpInterface.
However, this isn't very scalable since we actually rely on BreakOp methods in LoopOpInterface, where we only relied on the ConditionOp class before.

This PR moves the default implementation of cir::LoopOpInterface::getLoopOpSuccessorRegions into CIRDialect to resolve the dependency.

We may want to think of a more long term solution for handling CIR interfaces.
Should they be a separate build target?
Should they be within CIR dialect?
Should we move the implementation of interfaces into the CIR op themself, like we do for RegionBranchOpInterface? (I prefer this, personally)

[xlauko]

The problem is that LoopOpInterface does not link now with BreakOp?

In this case I would prefer removing the BreakOp dependency and adding LoopBreakingInterface.

[tommymcm]

The problem is that LoopOpInterface does not link now with BreakOp?

In this case I would prefer removing the BreakOp dependency and adding LoopBreakingInterface.

If I add some kind of LoopBreakingInterface, then interfaces need to link with CIR traits, since you need to check if the loop is the innermost Breakable parent of the BreakOp.
I think that the interfaces target should only have the interfaces, without default implementations. That way we never have to do these single-purpose interfaces for other operations. It also follows more closely with my understanding of the MLIR interface design.

[bcardosolopes]

This is not really NFC because you are changing the logic - cir::BreakOp is not there before (nor I did find anything in git history of it being there and getting removed). I understand the test for this will come later after we upstream some passes, and I'm fine with this as is, but the PR should have the accurate info!

[tommymcm]

Ope that's my bad. I thought I had already done the pr to add this handling. Thanks for the catch