Merge pull request !2186 from Kang/opt

Simplify node traversal strategy.

Add a case when the node is a parameter.

format

Standardize operation.

Signed-off-by: Hoai Linh Tran h00472437 <hoai.linh.tran@huawei.com>

Add optimizer checking: For a group of passes in "optimizer", if flagged then it will check and collect the newly generated nodes without types (i.e. abstract() == nullptr).
Before calling Renormalize(), the optimizer will check if there is any node needed retyping. If not the Renormalize pass will not be called.
Add checking for non-null abstract but still needs renorm;
Add flags to Substitution to help watching Renormalize

Simpler pass result checker, change Bool to Enum type

Signed-off-by: leonwanghui <leon.wanghui@huawei.com>