[MooreToCore]Unexpected observed values in llhd.wait.

Please check this PR(https://github.com/llvm/circt/pull/8210/files) to view the details.

Or for example:
```
moore.module @crash(in %in0: !moore.i32, in %in1: !moore.i32) {
%var = moore.variable :
moore.procedure always_comb {
%0 = moore.pows %in0, %in1 : !moore.i32
moore.blocking_assign %var, %0 : !moore.i32
moore.return
}
}
```

`%var` will be regarded as one member of the implicit sensitivity list. But this act is illegal❌.