keep original data_deps while resolving graph

[changhai0109]

Problem Related to the Feature

One of the future works on astrasim about memory requires getting the original data dependency from the workload. However, in the current implementation of ETFeeder the original data_deps will be mutated for recording dependency resolving.

Proposed Solution

Instead of directly mutating the data_deps in proto object, create another dependency list in the ETFeederNode or ETFeeder called unresolved_data_deps, which is mutatable and used to track the dependency resolving.

I will push a PR later to fix this issue.