[CIR] Early return in emitCXXTryStmt if try block is empty

[AmrDeveloper]

Currently, in the case of an empty try block, we emit tryOp in scope and revisit the catchers, and in the lowering pass, we have a check to delete empty scopes, but we end up with scopes that contains cir.yeild or an unconditioned jump to another scope which will not be deleted, also for catchers we emits globals for type info.

But we can already ignore the try-catch statement if the try block is empty, because that means also all catchers are dead code, which will lead to not emitting any scopes that we know will be removed later and also not emitting any unnecessary type info

Example of current emitted IR: https://godbolt.org/z/5d3jEe5K8