[mlir][dataflow] Fix DataFlowFramework crash by add isBlockEnd logic in the ProgramPoint::print (#173471)
Running -test-dead-code-analysis -debug on the following IR will trigger
a data-flow analysis framework assert, you can see
https://github.com/llvm/llvm-project/blob/2d6b1b174194198498eb10ae811632b3dd945ecf/mlir/include/mlir/Analysis/DataFlowFramework.h#L110
Fix DataFlowFramework crash by add isBlockEnd logic in the
ProgramPoint::print.
```
func.func @trs(%idx1: index, %idx2: index, %s: f32) {
scf.parallel (%i) = (%idx1) to (%idx2) step (%idx2) {
%r = memref.alloca() : memref<10xf32>
scf.forall (%e2) in (%idx2) {
%a = memref.load %r[%idx2] : memref<10xf32>
}
}
return
}
```